Textiloma (gossypiboma) mimicking recurrent intracranial tumor.

CONTEXT: Resorbable substances used to achieve hemostasis during neurosurgical procedures comprise 3 principal classes based on chemical composition: (1) gelatin sponge, (2) oxidized cellulose, and (3) microfibrillar collagen. Nonresorbable hemostatic aides include various forms of cotton and rayon-based hemostats (cottonoids and kites). Resorbable and nonresorbable hemostatic agents have been reported to cause symptomatic mass lesions, most commonly following intra-abdominal surgery. Histologic examination typically shows a core of degenerating hemostatic agent surrounded by an inflammatory reaction. Each agent exhibits distinctive morphologic features that often permit specific identification. Hemostat-associated mass lesions have been variously referred to as textilomas, gossypibomas, gauzomas, or muslinomas. OBJECTIVES: The aims of this study were to (1) identify cases of histologically proven cases of textiloma in neurosurgical operations, (2) characterize the specific hemostatic agent associated with textiloma formation, and (3) characterize the preoperative magnetic resonance imaging appearance of textiloma. DESIGN: Cases in which a textiloma constituted the sole finding on repeat surgery for recurrent brain tumor, or was a clinically significant component of a radiologically identified mass lesion together with residual tumor, constituted the study set. RESULTS: Five textilomas were identified and evaluated. The primary neoplasm was different in each case and included pituitary adenoma, tanycytic ependymoma, anaplastic astrocytoma, gliosarcoma, and oligodendroglioma. In all cases, preoperative magnetic resonance imaging suggested recurrent tumor. Textilomas included all categories of resorbable hemostatic agent. Other foreign bodies were present in some cases; the origin of these foreign bodies was traced to fibers shed from nonresorbable hemostatic material placed temporarily during surgery and removed before closure (cottonoids and kites). Inflammatory reactions included giant cells, granulomas, and fibroblastic proliferation. Microfibrillar collagen (Avitene) textilomas were associated with a striking eosinophil infiltration that was not seen with any other hemostatic agent. CONCLUSIONS: Hemostatic agents may produce clinically symptomatic, radiologically apparent mass lesions. When considering a mass lesion arising after intracranial surgery, the differential diagnosis should include textiloma along with recurrent tumor and radiation necrosis.

Intraparenchymal nevus cell aggregates in lymph nodes: a possible diagnostic pitfall with malignant melanoma and carcinoma.

It is well documented that nevus cells can be found within the fibrous capsule and trabeculae of lymph nodes; however, it is less well known that nevus cells can also be found in the lymph node parenchyma. We report the findings in 13 cases of nevus cell aggregates located within the cortical and/or medullary parenchyma of lymph nodes. Seven of the 13 patients had a primary diagnosis of melanoma, three had no known malignancy, one had breast carcinoma, one had adnexal carcinoma of the skin, and one had squamous cell carcinoma of the tonsil. Of the seven patients with melanoma, four had axillary lymph node dissections and three had inguinal lymph node dissections. The patient with adnexal carcinoma had metastatic carcinoma in 14 of 20 lymph nodes that had been dissected; one of them also had intraparenchymal nevus cells. The patient with squamous cell carcinoma of the tonsil had an intraparenchymal nevus cell aggregate in one of the 21 dissected lymph nodes; all 21 were negative for carcinoma. Nests of intraparenchymal nevus cells ranged from clusters of only a few cells up to 2.1-mm aggregates. No mitotic figures, prominent nucleoli, or lymphatic-vascular invasion were detected in any of the melanocytic aggregates. The melanocytic cells of the nevus cell aggregates expressed S-100 protein and/or MART-1 but not gp100 protein (HMB-45). Less than 1% of the nevus cells expressed Ki-67. The purpose of this study was to draw attention to the finding of nevus cells in the parenchyma of lymph nodes and to alert pathologists to this as a potential diagnostic pitfall, especially in patients with concurrent melanoma or carcinoma. Awareness that nevus cells can be present in nodal parenchyma, analysis of their morphologic features (including comparison with any previous or existing melanoma or carcinoma), and immunophenotyping will help pathologists to establish the correct diagnosis in most instances.

Extranodal follicular dendritic cell sarcoma of the head and neck region: three new cases, with a review of the literature.

Extranodal follicular dendritic cell (FDC) sarcoma of the head and neck region is uncommon, with 16 well-documented cases previously reported (four in the tonsil, four in the pharynx, two in the palate, five in the soft tissue, and one in the thyroid). We here report an additional three cases of extranodal FDC sarcoma in the tonsil (two cases) and pharynx (one case). In these new cases, the neoplastic cells were arranged in diffuse, fascicular, and vaguely whorled growth patterns. A background lymphocytic infiltrate was sprinkled throughout the neoplasms, with focal prominent perivascular cuffing. Scattered multinucleated giant cells were present. Immunohistochemically, tumor cells were strongly and diffusely positive for follicular dendritic cell markers CD21 and CD35. Tumor cells were diffusely positive for fascin and negative for leukocyte common antigen, S-100 protein, cytokeratin, and Epstein-Barr virus (EBV) latent membrane protein-1 (EBV-LMP). EBV was also not detected in the tumor cells by in situ hybridization for EBV-encoded RNAs. FDC sarcomas are probably an underrecognized neoplasm, especially when they occur in extranodal sites in the head and neck region. Two of the three new cases we report were initially misdiagnosed, and five cases of extranodal FDC sarcoma in the head and neck region reported in the recent literature were initially misdiagnosed. Our aim is to complement the current understanding of this neoplasm and alert pathologists to this rare entity in this region to avoid misdiagnosis. Recognition of extranodal FDC sarcoma requires a high index of suspicion, but this tumor has numerous distinctive histological features that should bring the neoplasm into the differential diagnosis. Confirmatory immunohistochemical staining with follicular dendritic cell markers such as CD21 and/or CD35 is essential for the diagnosis. Correct characterization of this neoplasm is imperative given its potential for recurrence and metastasis.