Myeloid sarcoma and extramedullary hematopoiesis expand the spectrum of ERG-positive proliferations: an ancillary tool in the diagnosis.

ERG overexpression has been linked to acute myeloid leukemia/myeloid sarcoma (MS). The aim of our study was to identify the frequency of ERG immunohistochemical (IHC) expression in MS (n = 21), blastic plasmacytoid dendritic cell neoplasms (BPDCNs; n = 8), extramedullary hematopoiesis (EMH: n = 9), normal and pathological bone marrow trephine biopsies (BM-TBs, n = 18), and the marrow component of adrenal myelolipomas (n = 15). ERG-positive and ERG-negative immunostains were identified in 68.

Monotypic Plasma Cell Proliferation of Uncertain Clinical Significance Mimicking Interstitial Cystitis: An Early Lesion of MALT Lymphoma?

We prospectively studied our institutional experience of bladder extranodal marginal zone (mucosa-associated lymphoid tissue [MALT]) lymphoma including bladder biopsies in which the possibility of MALT lymphoma was considered. We identified a subset of cases primary to the urinary bladder, presenting with prominent plasma cell infiltrates and symptoms mimicking bladder pain syndrome/interstitial cystitis. These proliferations were designated for this study as "monotypic plasma cell proliferation of uncertain clinical significance" (MPCP-US), as the features were insufficient for diagnosis of MALT lymphoma.

Fine needle aspiration biopsy of neuroendocrine breast carcinoma metastatic to the thyroid. A case report.

Background: Tumors showing neuroendocrine differentiation arise in a wide range of organs, and metastatic neuroendocrine tumors may be difficult to differentiate from primary tumors. This report describes an unusual case of metastatic breast carcinoma with neuroendocrine differentiation that presented as a solitary thyroid nodule. The diagnosis was made by fine needle aspiration biopsy (FNAB).