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466
C. L. Ward and E. P. Lamb
• Distant metastases delineate stage IV disease.
• Operative management principles:
– Wide local excision—based on Breslow thickness. You
must know and be ready to discuss margins.
Breslow thickness Margin
Melanoma in situ 0.5cm
<1.0mm 1.0cm
1.0–2.0mm 1.0–2.0cm
>2.0mm 2.0cm
– Sentinel node biopsy—be able to describe the proce-
dure including the utilization of both isosulfan blue
and radioactive tracer.
– Completion lymph node dissection—no longer rou-
tinely indicated for positive sentinel lymph nodes, but
should be discussed.
Complete lymph node dissection is indicated for
clinically positive nodes without radiologic evidence of distant metastases.
Unnecessary but if knowledgeable can cite relevant
studies in regard to this decision—MSLT-II and
DeCOG-SLT trials.
• Treatment strategies are based on six groups:
1. Stage 0 or small (<0.8mm) stage IA melanomas
– Management: wide local excision, no SLNB
2. Thin (0.8–1.0mm) T1B and thick (1.0–2.0mm) T2a
without ulceration
– Management: wide local excision, SLNB
3. Thin (0.8–1.0mm) T1B with ulceration or high mitotic
rate or T2b without clinically positive nodes
– Management: wide local excision, SLNB
– If SLNB is positive, the patient is upstaged to stage
III.
4. Stage III with clinically negative nodes
– Requires additional staging workup including
BRAF mutation testing and imaging.
– Wide local excision, SLNB (should already have
been completed).
– With positive SLNB and clinically negative nodes,
can consider completion lymph node dissection or
close radiologic and clinical surveillance.
– Consider systemic therapy vs. observation.
5. Stage III with clinically positive nodes, microscopic
satellites, or in-transit disease
– Requires additional staging workup including
BRAF mutation testing and imaging.
– If clinically palpable nodes, biopsy nodes rst to
conrm; then perform further imaging to evaluate
resectability of lymph node basins.
If resectable, consider neoadjuvant therapy in a
clinical trial, and perform wide local excision of
primary lesion and therapeutic lymph node dissection concurrently.
• Postoperatively, consider radiation to the
lymph node basin and systemic therapy.
If unresectable, offer systemic therapy, palliative
radiation, or intralesional injection.
6. Stage IV
– Management: systemic therapy, palliative excision,
palliative radiation
• Postoperative management:
– Radiation therapy:
Radiation is rarely indicated after complete surgical
excision of a primary melanoma.
Consider in patients with positive excision margins,
exceptionally thick melanomas (>4mm), or melanomas of the head or neck.
– Chemotherapy:
Neither neoadjuvant nor adjuvant chemotherapy or
targeted immunotherapy is recommended for
patients with stage I/II disease.
Further discussion in the “Thick Melanoma”
chapter.
– Surveillance:
Skin examination performed every 3–12 months by
a clinician for life, based on stage.
Regional lymph node ultrasound should be considered in patients with an equivocal lymph node physical exam, patients who qualied but did not
undergo a successful SLNB, and patients with a
positive SLNB without a completion lymph node
dissection.
Targeted imaging as directed by physical exam and
history.
Common Curveballs
• Excisional biopsy had negative margins <1 mm for a
0.6mm melanoma.
• Role of molecular testing.
• Lymph nodes will be clinically palpable.
• Lesion is now on the patient’s forehead.
• Will be other melanomas if you don’t say you will do
proper/complete skin survey.
Clean Kills
• Failure to explore history of risk factors, elicit history of
skin lesion including presence or absence of ulceration, or
perform a complete skin and lymph node examination
• Failing to counsel patient about future sun exposure and
tanning
• Doesn’t know the ABCDs to distinguish pigmented
lesions
135 Melanoma (Thin)
467
• Failing to perform proper skin biopsy (full thickness)
• Unable to state margins based on Breslow thickness
• Inappropriate performance of SLNB on thin melanoma
without ulceration or palpable lymph nodes
Bonus Points
• Understands the clinical importance of bleeding and
ulceration
• Knows pathologic criteria (mitoses, lymphovascular
invasion)
• Knows online nomogram which calculates risk of lymph
node metastasis
Words ofWisdom
Thin melanomas should be a simple, straightforward management discussion. Be deliberate and methodical, and get
ready for multiple scenario changes. Get the history, perform
a thorough physical exam including lymph node exam,
biopsy, and then excise with appropriate margins. If thin and
not ulcerated, SLNB is rarely indicated. Postoperative chemotherapy or radiation is unlikely in this scenario, but you
should be prepared to discuss surveillance strategies.
To Simplify:
1. Get a history and risk factors
2. Biopsy
3. Excise
(a) If thin (<0.8mm) and nonulcerated, excise with ade-
quate margins based on Breslow depth.
(b) If thin and ulcerated, excise with adequate margins
and perform SLNB.
4. Surveil
Bibliography
Referenced with permission from the NCCN Clinical Practice
Guidelines in Oncology (NCCN Guidelines®) for Melanoma:
Cutaneous V.2.2023. © National Comprehensive Cancer Network,
Inc. 2023. All rights reserved. Accessed June 18, 2023. To view
the most recent and complete version of the guideline, go online
to NCCN.org.
Melanoma (Thick)
CandaceL.Ward andElenaPaulusLamb
136
Way Question May BeAsked?
“A 57-year-old male presents to your ofce after a referral
from his primary care physician for a skin lesion on his right
shoulder. He is a nonsmoker and fair-skinned. He has no past
medical history and is an avid surfer. He has never had skin
lesions before and has no relevant family history.”
How toAnswer?
• Complete history and physical: same as for thin
melanoma
• Diagnostic workup: same as for thin melanoma
• Considerations prior to surgical intervention:
– Staging:
– T stage: “Thick” melanoma is >1mm in thickness.
T2a is >1.0 – 2.0 mm without ulceration and is
treated similarly to thin melanoma.
Anything above 1 mm Breslow thickness should
undergo a sentinel lymph node biopsy (SLNB).
• No SLNB: clinical stage IA, T1a melanoma
without other adverse features.
• Consider SLNB if clinical stage IB, T1b melanoma, or T1a lesions >0.5 with other adverse
features. It is worthwhile to present these at a
tumor board for discussion.
N stage: Perform SLNB on all stage II and above
with preoperative lymphoscintigraphy and intraoperative intradermal isosulfan blue dye injection.
• Stage II begins with lesions T2b.
• Nodal status correlates best with survival.
• Perform SLNB at same procedure as wide local
excision if able.
C. L. Ward (*) · E. P. Lamb
Department of Surgery, Jefferson Einstein Medical Center
Philadelphia, Philadelphia, PA, USA
e-mail: Elena.Lamb@jefferson.edu
M stage: imaging preoperatively based on physical
exam and history.
Provide an educated determination of stage:
• Patients with in situ melanoma are stage 0.
• Those with invasive melanoma and clinically
negative lymph nodes are stage I–II.
– Stage I: <1mm thick with (stage IB) or with-
out (IA) ulceration and mitotic rate 0/mm
– Stage II: >1 mm thick lesion with any fea-
tures and clinically negative nodes
• Patients with palpable lymph nodes, in-transit
disease, or microsatellites are stage III.
– Positive sentinel lymph nodes upstage mela-
noma to stage III at minimum.
• Distant metastases delineate stage IV disease.
• Operative management principles:
– Wide local excision—based on Breslow thickness. You
must know and be ready to discuss margins.
Breslow thickness Margin
Melanoma in situ 0.5cm
<1.0mm 1.0cm
1.0–2.0mm 1.0–2.0cm
>2.0mm 2.0cm
>2mm Breslow thickness melanoma will always have
a margin of 2cm.
– Sentinel node biopsy—be able to describe the proce-
dure including the utilization of both isosulfan blue
and radioactive tracer.
If the lesion is in an area without a clearly dened
or examinable lymph node basin, preoperative lymphoscintigraphy is recommended to identify draining lymph nodes.
– Completion lymph node dissection—no longer rou-
tinely indicated for positive sentinel lymph node but
should be discussed.
Complete lymph node dissection is indicated for
clinically positive nodes without radiologic evidence of distant metastases.
2
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2025
M. Neff et al. (eds.), Passing the General Surgery Oral Board Exam, https://doi.org/10.1007/978-3-031-78244-2_136
469
470
C. L. Ward and E. P. Lamb
Unnecessary but if knowledgeable can cite relevant
studies in regard to this decision—MSLT-II and
DeCOG-SLT trials.
• Treatment strategies are based on six groups:
1. Stage 0 or small (<0.8 mm) stage IA or IB
melanomas
– Management: wide local excision, no SLNB
2. Moderate thickness (0.8 – 1.0 mm) stage IA without
ulceration
– Management: wide local excision, no SLNB
3. Moderate thickness (0.8 – 1.0 mm) stage IB with
ulceration or high mitotic rate or stage II melanoma
without clinically positive nodes
– Management: wide local excision, SLNB
– If SLNB is positive, the patient is upstaged to
stage III.
4. Stage III with clinically negative nodes
– Requires additional staging workup including
BRAF mutation testing and imaging.
– Wide local excision, SLNB (should already have
been completed).
– With positive SLNB and clinically negative nodes,
can consider completion lymph node dissection or
close radiologic and clinical surveillance.
– Consider systemic therapy vs. observation.
5. Stage III with clinically positive nodes, microscopic
satellites, or in-transit disease
– Requires additional staging workup including
BRAF mutation testing and imaging
– If clinically palpable nodes, biopsy nodes rst to
conrm; then perform further imaging to evaluate
resectability of lymph node basins.
If resectable, consider neoadjuvant therapy in a
clinical trial and perform wide local excision of
primary lesion and therapeutic lymph node dissection concurrently.
• Postoperatively, consider radiation to the
lymph node basin and systemic therapy.
If unresectable, offer systemic therapy, palliative
radiation, or intralesional injection.
6. Stage IV
– Management: systemic therapy, palliative excision,
palliative radiation
• Postoperative management:
– Radiation therapy:
Radiation is rarely indicated after complete surgical
excision of a primary melanoma.
Consider in patients with positive excision margins,
exceptionally thick melanomas (> 4 mm), or melanomas of the head or neck.
– Chemotherapy:
Choice of adjuvant systemic therapy should take
into consideration the patient’s risk of melanoma
recurrence and the risk of treatment toxicity.
• Preferred regimens
– Nivolumab
– Pembrolizumab
– Dabrafenib/trametinib for patients with
BRAF V600-activating mutations
• Observation
– Surveillance:
Skin examination performed every 3–12 months by
a clinician for life, based on stage.
Regional lymph node ultrasound should be considered in patients with an equivocal lymph node physical exam, patients who qualied but did not
undergo a successful SLNB, and patients with a
positive SLNB without a completion lymph node
dissection.
Targeted imaging as directed by physical exam and
history.
Common Curveballs
• Lesion is 1.2mm thick without ulceration.
• Pre-op lymphoscintigraphy will light up several nodal
basins.
• Lymph nodes will be clinically palpable.
• Sentinel lymph node biopsy won’t work.
• There will be in-transit disease.
• Will be other melanomas if you don’t do complete skin
survey.
• Patient will have allergic reaction to blue dye. What is the
treatment?
• Decline in pulse oximetry reading during operative procedure (typical side effect of blue dye).
Clean Kills
• Failure to explore history of risk factors, elicit history of
skin lesion including presence or absence of ulceration,
or perform a complete skin and lymph node
examination
• Unable to state margins based on Breslow thickness
• Failure to perform SLNB on thick melanoma. Inability to
describe sentinel lymph node protocol/technique
• Unable to discuss consideration of completion lymph
node dissection and anatomic borders of dissection
136 Melanoma (Thick)
471
Bonus Points
• Can discuss in detail types of skin closure (skin graft or
tissue rearrangement)
• Can describe extent of complete node dissection of the
axilla and/or groin
• Understands use of radiation for lymph node-positive disease after node dissection
• Performs staging workup with total body PET, MRI of the
brain (CT chest/abdomen/pelvis if PET is not available)
• Understands the use of interferon-alpha 2b for nodepositive disease
Words ofWisdom
Thick melanomas add a level of complexity to appropriate
management. Sentinel lymph node biopsies should be completed with appropriate preoperative imaging if necessary.
Be prepared to discuss completion lymph node dissection
and when you would perform.
To Simplify:
1. Get a history and risk factors
2. Biopsy
3. Excise
(a) If moderately thick (>1.0–2.0 mm) and nonulcerated,
treat it like thin melanoma.
(b) If thick and/or ulcerated, perform SLNBx.
4. Consider systemic or radiation therapy
5. Surveil
Bibliography
Referenced with permission from the NCCN Clinical Practice
Guidelines in Oncology (NCCN Guidelines
Cutaneous V.2.2023. © National Comprehensive Cancer Network,
Inc. 2023. All rights reserved. Accessed June 18, 2023. To view
the most recent and complete version of the guideline, go online
to NCCN.org.
®
) for Melanoma:
Sarcoma
AliaAbdulla, CristaE.Horton, andCharlesShearer
137
Introduction
• STS most commonly occurs in the extremities (60%), followed by the trunk (25%) and pelvis/retroperitoneum
(15%).
• The most common location for STS is the proximal thigh
(44%), followed by the lower leg (27%), upper arm
(18%), and shoulder/axilla (11%).
• Genetic syndromes associated with STS: neurobromatosis type 1, Li-Fraumeni syndrome, familial adenomatous
polyposis (FAP) associated with desmoid tumors.
• The most common clinical presentation of STS is a painless mass, and retroperitoneal/pelvic STS present with
abdominal fullness, satiety, and may have associated
abdominal or ank pain without a palpable mass.
Retroperitoneal/abdominal STS usually present as large
masses and 70% are >10cm at diagnosis.
• The most common location for metastasis is the lungs.
STS spread hematogenously and are rarely associated
with lymphatic metastases.
Diagnosis
• Clinical: Thorough history and physical exam including
evaluation of neurovascular status of affected extremity.
For retroperitoneal masses, a thorough lymphatic and
genitourinary exam workup is necessary.
– Imaging
Plain radiograph and high-quality contrast- enhanced
CT or MRI of the entire compartment or for truncal
STS.
• These can potentially aid in clinical grading, as
well as distinguishing histologic subtypes based
on homogeneity of the tumor.
• Essential for surgical planning and assessing
anatomy and at-risk margins, which may lead to
discussion of neoadjuvant treatment to downgrade the tumor to eventually allow for a marginnegative resection.
• For abdominal and retroperitoneal STS, CT with
contrast is preferred to dene extent of tumor
including vascular structures and liver metastases.
– Biopsy
Image-guided core-needle biopsy, multiple passes
through a large >18-gauge needle. Determine histotype of the STS which determines treatment plan.
Incisional biopsy—for the nondiagnostic biopsy
occurring in 15% of patients, which should be conducted by the same surgeon who plans to conduct
the operation. The biopsy should be in the trajectory and should be included in the total planned
resection volume.
Excisional biopsy—for supercial, small tumors
(<3cm) in the extremity.
Fine-needle aspiration—lower diagnostic accuracy
rate (60–90%) than core-needle biopsy and often
not sufcient for establishing a diagnosis and grade.
However, it can conrm or rule out the presence of
a metastasis or local recurrence.
Histology
• Hematoxylin and eosin examination and
immunohistochemistry.
• Most common histological subtypes of sarcoma include
pleomorphic sarcoma (malignant brous histiocytoma),
GIST, liposarcoma, leiomyosarcoma, synovial sarcoma,
and malignant peripheral nerve sheath tumors.
A. Abdulla (*) · C. E. Horton
Department of Surgery, Broward Health Medical Center,
Fort Lauderdale, FL, USA
e-mail: chorton@browardhealth.org
C. Shearer
Florida International University College of Medicine,
Miami, FL, USA
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2025
M. Neff et al. (eds.), Passing the General Surgery Oral Board Exam, https://doi.org/10.1007/978-3-031-78244-2_137
Staging/grading—complete staging with CT of the chest
and compartment of the tumor
• AJCC staging system is divided based on anatomic site of
disease—considers tumor grade, size, nodal status, and
metastatic disease.
473
474
A. Abdulla et al.
• Grade is determined by histology and morphology—low,
intermediate, or high.
• STS most commonly metastasizes to the lung via hematogenous spread and rarely spreads via lymphatic
system.
Treatment
Operative Treatment
• Goals and standard of care
– Limb-sparing approach with vascular reconstruction if
necessary
– Function preserving
– Complete oncologic resection with negative margins,
ideally 1–2cm margins
Amputation necessary if the extremity STS is not ame-
nable to limb-sparing oncologic resection or not
amenable to limb salvage.
En bloc resection of contiguous organs or structures
for intra-abdominal and retroperitoneal STS.
An R1 resection can be considered if resection is with
signicant risk of complications or would be detrimental to a patient’s quality of life.
Steps for Operation of Extremity STS, Truncal STS, and
Abdominal/Retroperitoneal STS
Extremity and Truncal STS
• Incision made parallel to the long axis of the digit or limb,
which should include the previous biopsy site.
• Create skin aps and conduct wide local excision, with
2cm margins, with narrower margins near neurovascular
structures acceptable.
• Possibility of soft tissue ap reconstruction.
Intra-Abdominal or Retroperitoneal STS
• Incision is made in the midline to facilitate wide exposure
for circumferential dissection.
• En bloc resection of contiguous organs with resection of
major blood vessels.
• To attain an R0 resection, it may be necessary to deviate
from the usual plane of dissection if the sarcoma is inltrative to surrounding structures.
• Surgical clips left at areas concerning for positive margin
for assistance with adjuvant radiation therapy when
indicated.
• Closed suction drains at the discretion of the treating
surgeon.
• If positive margins, re-excision may be necessary or consideration of chemotherapy and/or radiation.
• Intra-Abdominal and Retroperitoneal STS have high
recurrence rates and complete resection is often not
acehievable.
• Palliative resection or debulking surgery may be considered to reduce symptoms of pain, obstruction, or
bleeding.
Nonoperative Treatments
• Radiation treatment
– Should be given to patients with large (>5 cm) high-
grade STS, which can be used in the postoperative
setting
• Chemotherapy
– Adjuvant chemotherapy for pelvic/retroperitoneal and
stage III extremity STS
• Nonoperative management for desmoid tumors preferred
due to high recurrence rate (>50%) after surgery, even
with negative margins
Management of Complications
• Surgical site infection, hematoma, seroma, wound
dehiscence
• Higher risk at previously radiated sites
• Negative pressure wound therapy or local wound care
techniques until ready for skin graft or soft tissue ap
coverage of dehisced wounds
• Long-term chronic edema or brosis
Follow-Up
• Multiple nomograms are available to predict risk of recur-
rence and outcomes in patients with STS.
• For patients with low-grade STS who have undergone
surgery with negative margins:
– Physical exam every 3–6 months for 2–3 years, then
annually thereafter
– Chest X-ray every 6–12 months
– Use of MRI or CT is based on risk of recurrence
• For patients with high-grade STS who have undergone
surgery with negative margins:
– Physical exam every 3–6 months for 2–3 years, then
every 6 months for the next 2 years, then annually
– Chest X-ray or CT of the chest
• Extremity STS should be followed with MRI with IV
contrast.
• Truncal, retroperitoneal, and pelvic STS should be followed with CT of the chest, abdomen, and pelvis with IV
contrast.
– These should be every 3–6 months for 2–3 years, then
every 6 months for 2 years, and then annually.
A 52-year-old man presents with complaints of early sati-
ety and abdominal fullness for several months. He undergoes
upper endoscopy and is found to have a smooth appearing
5×6cm mass in the distal stomach. Biopsy demonstrates
spindle cells positive for CD117 and CD34.
What is the likely pathology and what is the appropriate
management?
This lesion likely represents a gastrointestinal stromal
tumor (GIST), the most common sarcoma of the GI tract
originating from the interstitial cells of Cajal within the GI
myenteric plexus. CD117 is another name for the KIT gene,
137 Sarcoma
475
which codes for a tyrosine receptor kinase c-KIT, a protooncogene activated in 80% of GISTs. While a biopsy of
GISTs is not necessary preoperatively, the histologic conrmation would obviate the need for empiric lymphadenectomy as would be indicated for a neuroendocrine tumor or
adenocarcinoma, as GISTs rarely metastasize to lymph
nodes. Staging includes contrast CT of the chest, abdomen,
and pelvis. Resection in an open or minimally invasive
approach with grossly negative margins is satisfactory as
wide margins have not demonstrated a survival benet.
Resection should include care not to disrupt the capsule, as
rupture can cause seeding and adversely affect patient outcomes. Adjuvant therapy with imatinib, an oral tyrosine
kinase inhibitor of c-KIT, can be given for patients with
tumor spillage or high-risk features based on size and mitotic
rate. The length of duration and long-term toxicity of this
medication and individualization for patients with GISTs
have still not been established.
What are the main prognostic factors for GIST?
Tumor size and mitotic rate. Generally categorized as ve
mitoses per high-power eld, between ve and ten, and >10
mitoses per high-power eld. Size >5 cm deems a lower
prognosis. These prognostic variables allow for risk stratication and selection of patients for adjuvant therapy.
A 55-year-old man presents with the complaint of an
enlarging mass on the right side of his face for the past 2
years. The lesion started as a raised, esh-colored, xed
nodule with no discomforting symptoms before growing into
a currently disguring tumor with mild pain.
What is the next best step in diagnosis?
Core-needle biopsy or incisional biopsy.
The biopsy specimen demonstrates nger-like projections
of spindle cells, as well as detection of a genetic translocation causing PDGFB expression elevation. What is this
pathology and what is the management?
Dermatobrosarcoma protuberans (DFSP) is a rare, lowgrade sarcoma of the dermis that rarely metastasizes but is
locally aggressive and has high local recurrence. DFSP
appear as nodular, esh-colored, hard papules of the dermis
that grow slowly and persistently, sometimes mistaken for a
hypertrophic scar or keloid. The characteristic, nger-like
projections on histology likely account for high recurrence.
DFSP occurs most commonly in the fourth to seventh
decades of life and has equal distribution between men and
women with slight male predominance and is more common
in African Americans than Caucasians. Approximately 40%
arise from the trunk and the other 60% arise from the extremities or head and neck. Treatment is with wide local excision
with 2–4cm negative margins, without lymph node resection. Mohs also provides comparable results and may conserve more normal tissue. The 5-year survival rate of DFSP
is 99%. Imatinib can be used in locally advanced cases to
inhibit PDGFB expression frequently enhanced in DFSP.
A 58-year-old man presents to the clinic with a noticeable
lump on his lower back that has been progressively growing
over the past year. He reports mild discomfort and occasional pain in the area of the lump, especially when sitting or
lying down. Physical examination reveals a palpable, mobile,
and non-tender mass measuring approximately 7 cm in
diameter in the subcutaneous tissue of his lower back. The
patient’s medical history is unremarkable, and he has no signicant family history of cancer.
What would be the differential diagnosis for this patient?
Lipoma, liposarcoma, epidermoid cyst, broma, brosarcoma, rhabdomyosarcoma, malignant brous histiocytoma,
chondrosarcoma, osteosarcoma.
To evaluate and differentiate between lipoma and potential liposarcoma, what would be the next step for
evaluation?
Imaging and possible biopsy would represent the initial
workup. The patient undergoes imaging studies, including a
CT scan and MRI of the lower back. The images reveal a
well-dened, homogeneous mass consistent with a lipoma.
There is no evidence of thick internal septations, nonadipocytic areas, or lesions comprising <75% adipose tissue,
which are features more commonly associated with liposarcoma. It is essential to rule out the presence of malignant
features in patients with these symptoms and physical examination ndings.
Given the radiographic ndings, no immediate need for
biopsy is indicated, as the imaging does not raise suspicion of
dedifferentiation consistent with liposarcoma. If the imaging
had shown areas of necrosis or cystic change, focal nodular or
water density, or any other concerning features, a biopsy
would be recommended to denitively distinguish between
well-differentiated liposarcoma, dedifferentiated liposarcoma, and pleomorphic and myxoid/round cell liposarcoma.
What would the CT and MRI scans show for a
liposarcoma?
Features of liposarcoma as seen on CT include tumor size
larger than 10 cm, presence of thick septa more than 2mm,
and presence of non-adipocytic areas contributing to more
than 25% of the tissue.
What would be the treatment for this patient with a diagnosed lipoma?
Surgical excision beyond the capsule of the tumor to alleviate the patient’s symptoms of discomfort and ensure complete removal of the mass and prevent recurrence.
What would be the treatment if this patient had a possible
liposarcoma based on CT/MRI ndings?
The treatment of liposarcoma varies depending on its subtype and location:
476
A. Abdulla et al.
• Well-Differentiated Liposarcoma
– Location: may arise from retroperitoneum or
extremities
– Treatment:
Extremity Liposarcoma: Goal is limb-sparing
resection with a negative surgical margin.
Retroperitoneal Liposarcoma: Gross complete
resection is the primary goal.
Adjuvant therapy is typically not required for welldifferentiated liposarcoma due to its low risk of distant metastasis and resistance to radiation and
chemotherapy.
• Dedifferentiated Liposarcoma
– Location: may occur in extremities or
retroperitoneum
– Treatment:
Extremity Liposarcoma: Consideration of adjuvant
radiation therapy after resection.
Retroperitoneal Liposarcoma: Gross complete
resection is essential; adjuvant therapy may be
considered.
• Pleomorphic Liposarcoma
– Usually they are poorly differentiated.
– Treatment:
Resembles other poorly differentiated
liposarcomas.
Treatment strategy may vary depending on individual factors and response to therapy.
• Myxoid/Round Cell Liposarcoma
– Described by histologic appearance.
– Treatment:
Myxoid Liposarcoma: They often manifest as
slowly progressing, deep-seated tumors typically
located in the lower limbs. These tumors have the
potential to spread to various nearby soft tissue
areas such as the retroperitoneum. Therefore, it is
advisable to consider conducting CT scans of chest,
abdomen, and pelvis to properly assess staging.
Relatively sensitive to radiation and chemotherapy,
resulting in a favorable survival rate.
Round Cell Liposarcoma: Worse outcome than
myxoid liposarcoma, with a higher risk of
metastasis.
How would you distinguish well-differentiated and dedif-
ferentiated retroperitoneal liposarcomas?
MRI and CT scans are used for diagnosis. Suspicion of
dedifferentiated histology may include tumor hypervascularity, areas of necrosis or cystic change, adjacent organ invasion, and focal nodular or water density.
Biopsy can be used for denitive distinction between
well-differentiated and dedifferentiated histology.
Considerations for treatment regarding retroperitoneal
liposarcoma:
• Complex treatment due to the location.
• Primary goal is gross complete resection; incomplete
gross resection is associated with an increased risk of
mortality. Consideration for a “complete compartmental
resection” approach, which involves resection of contiguous organs when feasible.
• Treatment should be individualized based on factors such
as tumor biology, recurrence, and response to therapy.
Take-Home Point
This clinical scenario involves a patient with a subcutaneous
mass in the lower back that is initially suspected to be a
lipoma. Careful evaluation through imaging and consideration of clinical features is crucial to rule out the possibility
of liposarcoma, especially dedifferentiated liposarcoma, and
to provide appropriate treatment. If patients do have MRI
and CT ndings consistent with liposarcoma, biopsy, locations, and immunohistochemistry can be used to determine
and dictate treatment plans. Regular follow-up is essential to
monitor the patient’s condition and ensure the absence of any
recurrence or complications.
Bonus Points
• Demonstrating thorough knowledge of the molecular and
genetic abnormalities as they relate to the tumor biology
associated with STS. Recognizing how these variations
may relate to treatment and management
• Demonstration of in-depth knowledge of the different
stages of STS as well as grades and nomograms based on
particular societal guidelines
Clean Kills
• Not obtaining appropriate workup with regard to which
STS to biopsy or not biopsy
• Not demonstrating an understanding of which STS
require thorough staging workup based on features of
aggressiveness or high rates of recurrence
• Failing to evaluate for lung metastases prior to surgical
management
• Failure to consider factors necessitating discussion of
adjuvant therapy
• Not conducting an adequate history and physical
examination
• Utilizing incorrect imaging modalities or diagnostic techniques as they relate to specic STS types
137 Sarcoma
477
Words ofWisdom
While STS are rare, these complex tumors may provide a
strong opportunity for development of novel and targeted
therapies. Surgeons must demonstrate expertise in the presentation, diagnosis, tumor biology, and management of a
broad assortment of STS, as well as the potential risks and
complications of resection. Surgeons must also know the
indications for adjuvant therapy based on tumor biology and
location. It is important for surgeons to be aware that there
are a number of common, nonneoplastic conditions and
other malignant conditions that can mimic STS, so a rm
ability to distinguish these pathological discrepancies is
critical.
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