5.3Biopsy

5.3.1Noninfectious Necrotizing Scleritis

Histopathologically, most cases of noninfectious necrotizing scleritis show inßammatory microangiopathy (96% of sclera specimens and 70% of conjunctival specimens studied) as well as chronic granulomatous inßammation (85% of scleral specimens studied); most of these patients have a potentially lethal underlying systemic vasculitic disease (91% of all noninfectious necrotizing scleritis patients; see Chap. 4). However, scleral and/or conjunctival specimens from noninfectious necrotizing scleritis do not show histopathological Þndings distinguishing between the different systemic vasculitic diseases.

Because most cases of noninfectious necrotizing scleritis show histopathological evidence of inßammatory microangiopathy (96% of scleral specimens and 70% of conjunctival specimens studied), scleral and/or conjunctival biopsy in noninfectious necrotizing scleritis is not necessary to prove a vasculitic process. Because histopathological changes in noninfectious necrotizing scleritis are similar regardless of the type of associated systemic vasculitic disease, scleral and/or conjunctival biopsy in noninfectious necrotizing scleritis is not helpful in reaching the diagnosis of a speciÞc systemic vasculitic disease. Characteristic histopathological changes in biopsy material of involved extraocular tissues (necrotizing vasculitis with or without granulomas, with or without eosinophils, in small, medium, or large vessels), supplemented by compatible multisystem clinical Þndings, conÞrm the diagnosis of a speciÞc systemic vasculitic disease. The clinical detection of necrotizing scleritis conÞrms a local vasculitic process. The clinical detection of necrotizing scleritis supplemented by compatible multisystem clinical Þndings is highly suggestive of a speciÞc systemic vasculitic disease. The clinical detection of necrotizing scleritis in patients with already known connective tissue diseases is highly suggestive of a widespread vasculitic process. Either local or

systemic vasculitic processes should be treated with a high dosage of corticosteroids or other immunosuppressive drugs.

One exception to this is the need to speciÞcally prove a granulomatous process. Although a chronic granulomatous inßammation may appear in necrotizing scleritis associated with many vasculitic diseases (85% of scleral specimens studied), the presence of granulomas with or without inßammatory microangiopathy in scleral and/or conjunctival specimens conÞrms the diagnosis of granulomatosis with polyangiitis (Wegener) in a patient with compatible systemic clinical Þndings, such as chronic sinusitis, nasal ulceration, chronic cough, or hematuria, with or without positive ANCA testing. Histopathological detection of necrotizing granulomas with or without inßammatory microangiopathy in scleral and/or conjunctival specimens conÞrms the diagnosis of the highly limited form of granulomatosis with polyangiitis (Wegener) in a patient with necrotizing scleritis and positive ANCA testing. In the absence of positive ANCA testing, the presence of characteristic ocular histopathological Þndings without systemic clinical features does not support the diagnosis of granulomatosis with polyangiitis (Wegener). In the absence of characteristic ocular histopathological Þndings, a positive ANCA test is suggestive of highly limited granulomatosis with polyangiitis (Wegener), although not diagnostic. Granulomatosis with polyangiitis (Wegener) should be treated with cyclophosphamide.

5.3.2Noninfectious Recurrent Diffuse or Nodular (Nonnecrotizing) Scleritis

Histopathologically, some cases of noninfectious recurrent diffuse or nodular scleritis show inßammatory microangiopathy (61% of scleral specimens and 59% of conjunctival specimens studied) as well as chronic granulomatous inßammation (23% of scleral specimens studied); some of these patients have a potentially lethal underlying systemic vasculitic disease (43% of all noninfectious recurrent diffuse scleritis patients and 41%

of all noninfectious recurrent nodular scleritis patients; see Chap. 4). However, scleral and/or conjunctival specimens from noninfectious recurrent diffuse or nodular scleritis do not show histopathological Þndings distinguishing between the different systemic vasculitic diseases.

Because only some cases of noninfectious recurrent diffuse or nodular scleritis show inßammatory microangiopathy (61% of scleral specimens and 59% of conjunctival specimens studied), scleral and/or conjunctival biopsy in recurrent and severe diffuse or nodular scleritis may be helpful in detecting an underlying local and probably systemic vasculitic process, which should be treated with a high dosage of corticosteroids or other immunosuppressive drugs; histopathological detection of inßammatory microangiopathy with or without granulomas in scleral and/or conjunctival biopsy in recurrent and severe diffuse or nodular scleritis, supplemented by compatible multisystem clinical Þndings, is highly suggestive of a speciÞc systemic vasculitic disease. The Þnding of characteristic histopathological changes in biopsy material of involved extraocular tissues, supplemented by compatible multisystem clinical Þndings, conÞrms a speciÞc vasculitic disease.

Scleral and/or conjunctival biopsy in recurrent and severe diffuse or nodular scleritis also may be helpful in detecting a granulomatous process. Although a chronic granulomatous inßammation may appear in diffuse or nodular scleritis associated with many vasculitic diseases (23% of scleral specimens studied), the presence of granulomas with or without inßammatory microangiopathy in scleral and/or conjunctival specimens, in association with complete and, especially, limited clinical features, conÞrms the diagnosis of granulomatosis with polyangiitis (Wegener) with or without positive ANCA testing. Histopathological detection of granulomas with or without inßammatory microangiopathy in scleral and/or conjunctival specimens conÞrms the diagnosis of the highly limited form of granulomatosis with polyangiitis (Wegener) in a patient with recurrent diffuse or nodular scleritis and positive ANCA testing. In the absence of positive ANCA testing, the presence of characteristic ocular

histopathological Þndings without systemic clinical features does not support the diagnosis of granulomatosis with polyangiitis (Wegener). In the absence of characteristic ocular histopathological Þndings, a positive ANCA test is suggestive of highly limited granulomatosis with polyangiitis (Wegener), although not diagnostic.

5.3.3Infectious Scleritis (Diffuse, Nodular, or Necrotizing Scleritis)

In infectious scleritis, staining and cultures of scleral scrapings may demonstrate the microorganism implicated. However, when scrapings are negative, analysis of scleral and/or conjunctival specimens by light microscopy and appropriate staining (GramÕs stain, alkaline Giemsa, Gomori methenamine silver, WarthinÐStarry silver, acidfast, and calcoßuor white) may reveal the etiological agents, and subsequent culture of the tissues (blood agar, chocolate agar, Sabouraud dextrose agar, meat broth, PageÕs saline, and transfer to conßuent layers of E. coli) may help in further identiÞcation. Tissue homogenization and subsequent culture on different media or cell culture lines also may be important for microbe isolation. Indirect immunoßuorescence techniques may be helpful to identify HSV type 1 or T. pallidum.

5.3.4Biopsy Technique

Scleral biopsy is performed under retrobulbar anesthesia. After careful dissection of the conjunctiva, TenonÕs capsule, and episcleral tissue, inßamed or necrotic scleral tissue is removed. This is then bisected, and half is placed on KarnovskyÕs Þxative for histopathological evaluation; the remaining half is placed on saline and then transported to the cryostat, embedded in optimum cutting temperature (OCT) compound, and frozen immediately at −25¡C for immunoßuorescence evaluation. In cases in which the remaining sclera is thin, scleral graft is used to maintain the integrity of the globe. A template is made from plastic surgical drape to approximate the area of resected sclera. Frozen or