cause a paraneoplastic retinopathy resulting in changes similar to retinitis pigmentosa [217].

Plasmacytoma/Multiple Myeloma

Plasma cell myelomas (PCM) can be grouped based on whether they arise from the bone or are extramedullary and if they manifest as single (plasmacytoma) or multiple bone lesions (multiple myeloma). These share in common the over-secretion of monoclonal protein, most commonly excess IgG comprising about half of all affected, while Bence Jones protein (kappa or lambda light chains only) accounts for only 16% [218]. Systemic findings include lytic skeletal lesions, hypercalcemia, anemia of chronic disease, and acute renal failure, although there is a form of MM, smoldering MM, that can be entirely asymptomatic [197]. MM accounts for approximately 10% of all hematologic malignancies, with an incidence of 4 per 100,000 persons that increases with age and a slight male predominance [184, 219].

When the posterior pole is involved, the findings of MM are predominantly secondary to its systemic effects or from chemotherapy. Severe anemia may result in a non-proliferative diabetic retinopathy like fundus but with nerve fiber layer hemorrhages that may include white centers, occurring regardless of serum monoclonal protein levels [220]. The latter point may be due to the fact that like the IgM encountered in WM, but rarely, a hyperviscosity syndrome or CRVO can occur despite the presence of IgG protein [221].

MM seems to lack a strong tropism for the eye, but direct infiltration of the choroid and retina, temporal arteritis, vasculitis, peripheral cysts, and exudate macular detachments have been reported [222, 223]. Very rarely, a plasmacytoma may arise primarily in the choroid as an amelanotic mass [224].

Plasma Cell Leukemia

Plasma cell leukemias are rare and arise primarily or as a progression of multiple myeloma, with an overall incidence of 0.02 cases per 100,000 persons [142]. The diagnosis requires kappa or lambda light chain restriction and an absolute plasma cell count greater than 2,000/ml or 20% of

the peripheral white blood count [225]. Presenting signs and symptoms can include those of both multiple myeloma and leukemia. Therefore, leukemic findings, such as hemorrhage, CWS, perivasculitis, and chorioretinal infiltration, or features characteristic of multiple myeloma may become apparent.

T Cell Lymphomas

The T cell lymphomas are a small group of neoplasms that include adult T cell lymphoma/leukemia, cutaneous T cell lymphoma, anaplastic large cell lymphoma, angioimmunoblastic T cell lymphoma, and T-prolymphocytic lymphoma. The intraocular manifestations of T cell lymphoma are rare and, when present, have been more commonly associated with systemic involvement of primary cutaneous peripheral T cell lymphoma or adult T cell lymphoma/ leukemia rather than primary intraocular lymphoma, although clinically they may have a similar appearance and therefore require tissue or fluid specimens [169, 226].

In particular, adult T cell lymphoma/leukemia is the only T cell lymphoma due to human T-lymphotropic virus type 1 [144]. It is rare in the United States with 0.05 cases per 100,000 population and is more prevalent in the Caribbean and southern Japan with a slight male predominance [142, 227]. The exact mechanism of tumorigenesis is unclear although a viral oncoprotein, tax, appears to decrease apoptosis and favor cellular survival and proliferation [228]. Ocular involvement usually involves wide-ranging findings from vitritis, yellow-white choroidal or retinal infiltration, hemorrhage, edema, and rarely vasculitis and optic nerve infiltration, although the most frequent finding is vitritis [171, 226, 229].

Mycosis fungoides and its more aggressive variant, Sezary syndrome, characterize a unique and extremely rare subset of primary cutaneous T cell lymphomas of unclear cause with incidences of 6 and 0.3 cases per million population per year, respectively [230]. Although ocular involvement is rare, it can present with vitritis and white subretinal lesions between RPE and Bruch’s