IgG4-related disease has evolved from originally being recognized as a form of pancreatitis to encompass diseases of numerous organs including the hypophysis and one reported case of dural involvement. A search of the University of Virginia, Division of Neuropathology files for 10 years identified ten cases of unexplained lymphoplasmacytic meningeal inflammation that we then evaluated using immunohistochemical stains for IgG4 and IgG. Ten control cases including sarcoidosis (4), tuberculosis (1), bacterial abscess (2), Langerhans cell histiocytosis (2), and foreign body reaction (1) were also examined. The number of IgG4-positive plasma cells was counted in five high power fields (HPFs) and an average per HPF was calculated. Cases that contained greater than ten IgG4-positive cells/HPF were considered to be IgG4-related. Five of the study cases met these criteria, including one case of leptomeningeal inflammation. All cases exhibited the typical histological features of IgG4-related disease including lymphoplasmacytic inflammation, fibrosis, and phlebitis. The dural-based lesions appear to represent a subset of the cases historically diagnosed as idiopathic hypertrophic pachymeningitis. While the leptomeningeal process most closely resembles non-vasculitic autoimmune inflammatory meningoencephalitis. Given these findings, IgG4-related meningitis should be considered in the differential diagnosis of meningeal inflammatory lesions after stringent clinical and histologic criteria are used to rule out other possible diagnoses.

We reviewed 17 cases of primary anorectal malignant melanoma. Morphologic features evaluated included junctional change, pigmentation, morphology, and mitotic rate. Immunohistochemical stains were performed for/with S-100 protein, HMB-45, MelanA, tyrosinase, vimentin, KIT, and pankeratin. Morphologic subtypes were as follows: epithelioid, 12 cases; spindle cell, 7 cases; lymphoma-like, 10 cases; and pleomorphic, 6 cases. Pigmentation was present in 9 cases. Junctional change was present in 6 cases. The mitotic rate was 3 or more per high-power field in 8 cases. S-100 protein was present in all cases, HMB-45 stained 16 of 17, MelanA was present in 14 of 15, tyrosinase in 12 of 14, vimentin in 13 of 14, and KIT in 12 of 16. Pankeratin was absent in all cases. The mean length of follow-up was 25.6 months (range, 8-96 months), and the average survival with disease was 32.3 months (range, 8-96). No morphologic or immunohistochemical features were predictive of survival. Anorectal malignant melanoma shows considerable morphologic variability. Immunohistochemical staining is similar to cutaneous melanomas. Expression of KIT was present frequently, including cases with spindle cell morphologic features, in which it may lead to confusion with gastrointestinal stromal tumors.

Natural killer (NK)-like T cells are major histocompatibility complex- unrestricted cytotoxic T cells that are surface CD3-positive, express NK-cell antigens, and rearrange their T-cell receptor. Most neoplasms arising from this T-cell subpopulation have been a chronic lymphoproliferative disease referred to as T-large granular lymphocyte (LGL) leukemia. Only 10 NK-like T-cell lymphomas have been described in detail previously; this study presents the clinicopathologic features of six others and distinguishes these lymphomas from T-LGL leukemia. All patients presented with B-symptoms and often had marked hepatosplenomegaly without significant peripheral lymphadenopathy. Four of the six patients were immunosuppressed. All had CD3, CD8, CD56- positive tumors, presumably of hepatosplenic (n = 3), intestinal (n = 1), pulmonary (n = 1), or nodal (n = 1) origin. Three patients had lymphomatous bone marrow infiltrates, and four had peripheral blood involvement by neoplastic large lymphocytes, some of which had a blastic appearance or resembled virocytes. Azurophilic granules, ultrastructurally corresponding to cytoplasmic dense core and/or double density granules, were seen in all cases. T-cell clonality was shown in five tumors by Southern blot analysis, and three had abnormal karyotypes. Two untreated patients died 20 days after presentation, and three patients who received combination chemotherapy died within 5 months of presentation. One patient remains in complete remission 22 months after treatment. These findings suggest NK-like T-cell lymphomas are aggressive, are clinicopathologically distinct from T-LGL leukemia, and should be in the differential diagnosis of extranodal T-cell lymphoproliferations, including those in immunosuppressed patients. Furthermore, the LGL morphology, phenotype, and tissue distribution of some NK-like T-cell lymphomas suggest they arise from thymic- independent T cells of the hepatic sinusoids and intestinal mucosa.

No abstract

TCRBCLs are difficult to recognize without immunoperoxidase studies. Patients with TCRBCL have clinical features similar to patients with other large B-cell lymphomas, except they may have more splenomegaly and advanced-stage disease; they should receive combination chemotherapy directed at large-cell lymphomas.