Introduction/Objective Extranodal marginal zone lymphoma (MZL) is a rare indolent tumor with the potential of recurrence and systemic spread. Thyroid involvement is infrequently reported, and generally seen in the context of Hashimoto thyroiditis. Additionally, amyloid deposition is an exceptional complication of extranodal MZL. We report an unusual case of a 65-year-old woman with a rapidly growing symptomatic nodule of the right thyroid lobe and a previous inconclusive FNA showing benign lymphoid tissue. She was taken to the OR for diagnostic right thyroid lobectomy with neck level 6 dissection. Methods/Case Report The specimen was sent for histologic evaluation, and showed thyroid with marked amyloid deposition, highlighted by Congo Red special stain, distorting normal architecture. Additionally, significant small atypical lymphoid infiltrate was present. Neoplastic lymphocytes were positive for CD20, PAX5 and CD43. Kappa light chain restriction by kappa ISH stain indicated monoclonality. Conversely, CD138, CD10, BCL6 and CyclinD were negative. Ki-67 demonstrated a 15-20% proliferation index. The germinal centers of the secondary follicles demonstrated diminished CD10 and BCL-6 consistent with follicular colonization by neoplastic lymphocytes. One of the regional lymph nodes displayed involvement by lymphoma with amyloid deposition. Medullary carcinoma of the thyroid was ruled out on the basis of incompatible histologic and immunohistochemical profile. Results (if a Case Study enter NA) NA Conclusion While Medullary carcinoma and amyloid goiter are among the top differentials for extensive amyloid deposition in the thyroid gland, we illustrate the need for judicious review of clinical history and careful consideration of immunohistochemistry workup to establish the unusual diagnosis of extranodal MZL of the thyroid with extensive amyloid deposition.

Introduction/Objective The co-occurrence of essential thrombocythemia (ET) and multiple myeloma (MM), two distinct entities with distinct cellular origin, is rare, with a limited number of cases reported. Methods/Case Report We report a case of a 63-year-old male who initially presented with thrombocytosis, splenomegaly and elevated LDH. A bone marrow examination showed hypercellularity (90%) with increased abnormal megakaryocytes, as well as a JAK2 V617F mutation, with overall features consistent with involvement by a myeloproliferative neoplasm (MPN), consistent with ET (versus early primary myelofibrosis (PMF)). Additionally, 6% kappa-restricted plasma cells were identified, consistent with involvement by a monoclonal gammopathy of undetermined significance (MGUS). The patient was subsequently treated with hydroxyurea. Four years later, he presented with evidence of paraproteinemia. IgG kappa monoclonal paraprotein was elevated at 3.4 g/dL. A repeat bone marrow examination showed hyper-cellularity (60%), including clusters of abnormal megakaryocytes and mild to moderate reticulin fibrosis. The previously identified kappa-restricted plasma cell population increased to approximately 40% of the total cellularity. Cytogenetic analysis showed a normal male karyotype (46,XY[20]), and a prognostic myeloma-FISH panel including 13q-/-13, 1q32/1q21, p53/NF1, CCND1/IgH t(11;14), FGFR3/IgH t(4;14), IgH/MAF t(14;16) and IgH/MAFB t(14;20) was negative for all tested abnormalities. The overall features were again consistent with involvement by an MPN and progression of the previously identified MGUS. Results (if a Case Study enter NA) NA. Conclusion Only a few cases of concurrent ET and MM have been previously reported in the literature, with most of these cases having a temporal association with alkylating agent therapy. However, MM development has also been reported in a patient with non-cytotoxic treatment of ET. In contrast, our patient was diagnosed with ET associated with MGUS at the initial diagnosis. Notably, the co-existence of early PMF with MM appears to be relatively more established. A large study showed that previous PMF was strongly associated with MM development (OR 24.3; 95% CI:2.9-201.5).

Introduction/Objective Solitary fibrous tumor (SFT) is an uncommon mesenchymal neoplasm, and may involve many anatomic locations. Approximately 0.6% of SFTs in the oral cavity and maxillofacial complex may recur and/or develop distant metastasis. Here we report a case of SFT in oral cavity with local recurrence and distant metastasis. Methods/Case Report The patient was a 66-year-old male with a past medical history of left buccal mass status post excision with an unclear diagnosis in a foreign country 6 years ago. He presented with a recurrence of the left buccal mass. Computerized tomography (CT) of the head and chest demonstrated a 9 cm expansile mass centered in the left pterygopalatine fossa and a 1.7 cm mass in left upper lobe of the lung, respectively. Biopsy of the lung mass was performed first and displayed a hypercellular mesenchymal tumor, composed of spindle cells arranged in vague short fascicles, and scant fibrous stroma with thin-walled and staghorn-like vasculature. The tumor cells had mild nuclear atypia with 5 mitoses/10 high power fields. No necrosis is identified. There were trapped benign pneumocytes and bronchial epithelial cells in the tumor. The tumor is positive for CD34, CD99, Bcl-2 and STAT6 immunostains. The large left buccal mass was biopsied later and showed similar morphology. The diagnoses of metastatic SFT in the lung and recurrent SFT were rendered, respectively. Results (if a Case Study enter NA) NA. Conclusion The histologic findings of the recurrent SFT and the pulmonary metastasis are similar in our case. Although marked cellular atypia and necrosis are not observed in either tumor, other features including the large size of recurrent tumor, hypercellularity, and increased mitotic activity are associated with malignant behavior in this report, and warrant the need for long-term follow-up.