Membranous basal cell adenoma (MBCA) is a rare benign salivary gland neoplasm. It is difficult to diagnose MBCA based on fine-needle aspiration (FNA) cytology due to rare reporting of its FNA cytology and overlapping of its FNA cytologic features with some benign and malignant entities. We present a case of MBCA in a 67-year-old female that was originally misinterpreted as adenoid cystic carcinoma (ACC) on FNA cytology. The FNA smears showed numerous uniform small basaloid epithelial cells with round or oval nuclei and inconspicuous nucleoli, and scant cytoplasm. The basaloid cells surround acellular, dense, homogenous material or are surrounded by acellular or paucicellular dense homogeneous material possibly containing bland spindle cells. The basaloid cells are present in variably sized three-dimensional clusters, acini, or sheets with variable cohesion. The dense homogenous material surrounded by basaloid cells may be interconnected. High power magnification reveals the homogeneous material to have a fibrillar texture. The edges of dense homogenous materials were well-demarcated. We describe the diagnostic pitfalls of FNA for MBCA, particularly versus ACC, basal cell adenoma, cellular pleomorphic adenoma, myoepithelioma, basal cell adenocarcinoma, and basaloid squamous cell carcinoma in hope of improving clinical management and patient treatment.

Epithelioid hemangioendothelioma (EHE) of the liver is an extremely rare tumor that masquerades as an epithelial neoplasm and poses significant diagnostic pitfalls for the cytopathologist. This report describes a 64-year-old woman whom on computerized tomography was found to have multiple peripherally calcified hypodense lesions throughout the liver and an ipsilateral adrenal mass. Fine needle aspiration and needle cores biopsies of the largest liver lesion showed epithelioid cells and spindle cells in fibrous stroma. The epithelioid cells had round or oval, hyperchromatic nuclei with smooth nuclear contours, delicate cytoplasm and indistinct cytoplasmic borders. Rare cells had intracellular vascular lumen containing fragmented or intact red blood cells. The cells were individually dispersed or arranged in nests and vague tubular arrays. No mitotic figures or necrosis were seen. An immunohistochemical profile demonstrated diffuse CD31 and focal CD 34 and nuclear Fli-1 immunoexpression and low Ki-67 proliferative activity (1%) within lesional cells confirming the diagnosis of EHE. The differential diagnosis of EHE which includes cholangiocarcinoma, hepatocellular carcinoma, metastatic carcinoma and melanoma is discussed.

We describe the first cytology case report of an intraductal oncocytic papillary neoplasm (IOPN) of the liver. A 51-year-old male presented with recurrent cholangitis. Magnetic resonance imaging and endoscopic retrograde cholangiopancreatogram revealed a 1.1 × 0.9 cm polypoid lesion within the left intrahepatic bile duct. Fine-needle aspiration and needle core biopsy (NCB) revealed nests, 3-dimensional or papillary clusters of columnar or cuboidal cells with loss of polarity. The nuclei were uniform with even chromatin, and cytoplasm was granular or vacuolated. No mitosis or necrosis was seen. The cytologic and histologic diagnosis was "consistent with Intraductal Oncocytic Papillary Neoplasm (IOPN), intermediate grade (borderline)." The patient then underwent a left lateral liver segmentectomy. Microscopic examination showed histology similar to the NCB with no stromal invasion identified. Hepatic IOPN poses a diagnostic challenge due to its broad differential diagnoses. Both malignant and non-malignant IOPNs may present with similar clinical symptoms, pathology, histology, cytomorphology, and immunohistochemistry. Hepatic IOPN should be excised as it is a precursor lesion of adenocarcinoma.