IgG4-related disease is an uncommon sclerosing and inflammatory mass-forming disease that may affect a single organ or be systemic. The prototypical example of the disease is type 1 autoimmune pancreatitis. After the pancreatobiliary system, the head and neck is the next most common site for involvement by IgG4-related disease. Here, we describe the clinicopathologic features of the head and neck involvement by this disease process with particular attention to involvement of the major salivary glands, the lacrimal glands and periorbital tissues, the upper aerodigestive tract, the thyroid gland, lymph nodes, the ear, and the skin and soft tissues.

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A previously healthy 62-year-old woman was taken to surgery for partial thyroidectomy for a suspected colloid nodule. A small level VI lymph node was found incidentally during surgery. The lymph node was 0.5 cm in greatest dimension. The architecture was effaced by a nodular proliferation of neoplastic cells (panel A). The follicles showed a reverse pattern with large centroblasts at the periphery of the neoplastic follicles and the small centrocytes in the center (panel B). Immunohistochemistry was performed on the tissue; the neoplastic cells were immunoreactive with CD20, CD10, bcl-2, bcl-6, and CD21 (panels C-G) and negative for CD3, CD5, and bcl-1. Fluorescent in situ hybridization with break-apart probes showed disrupted bcl-2 (panel H) and bcl-6 genes with an intact C-myc gene.The patient was diagnosed with follicular lymphoma, grade 3B, follicular pattern. The unique morphologic feature of this case is that of a reverse variant of follicular lymphoma. The reverse (peripheral) grouping of the large cells in the follicles makes grading difficult. Positron emission tomography scan was performed on the patient and showed extensive neck, chest, and abdominal lymphadenopathy with abnormal fludeoxyglucose uptake. At diagnosis, the patient was asymptomatic and this was an incidental finding in a small lymph node.For additional images, visit the ASH IMAGE BANK, a reference and teaching tool that is continually updated with new atlas and case study images. For more information visit http://imagebank.hematology.org.

Case Report AbstractPoorly differentiated neuroendocrine tumors are uncommon tumors of the GI tract and often diagnosed without the identification of the primary site. Here, we describe a case of poorly differentiated neuroendocrine carcinoma of unknown primary that is diagnosed by bone marrow biopsy. A68-year-old male patient presented with worsening back pain, hypercalcemia, anemia, and altered mental status. Initially, imaging favored multiple myeloma. However, a bone marrow biopsy revealed morphologic and immunohistochemical features of neuroendocrine origin.