Primary Lung Intravascular Large B-Cell Lymphoma Clinically Mimicking Sarcoidosis: A Rare Case Report and Review of Literature

We present a case of a 73-year-old male who initially presented with night sweats, intermittent fever, worsening dry cough and shortness of breath. CT scans revealed atelectasis and calcified mediastinal lymphadenopathy, raising a suspicion for sarcoidosis. Multiple lung biopsies were performed. Microscopically, atypical lymphocytes were identified within capillaries, small arteries and veins. These lymphocytes were large with prominent nucleoli. Immunohistochemical staining demonstrated tumor cells positive for CD20, CD79a, Pax-5, CD10 and Mum-1, while negative for CD3, cytokeratin, S100, and CD34. LDH serum level was increased (480 IU/L). Extra pulmonary lymphoma was not detected elsewhere in the patient. These findings support the diagnosis of primary lung intravascular large B cell lymphoma (IVLBCL). Literature review of 52 cases demonstrated occurrence of primary lung IVBCL in patients between the ages (35–85) with a slight male predominance (1.167:1). The most common clinical presentation was fever associated with dyspnea

Sentinel Lymph Node Involvement by Epithelial Inclusions Mimicking Metastatic Carcinoma: A Diagnostic Pitfall

Objective: Background: Rare disease An epithelial inclusion cyst within a lymph node denotes a heterotopic phenomenon. Nodal epithelial inclusion cysts have been reported in a variety of anatomical locations including pelvic, abdominal, mediastinal, and axillary regions. While nodal melanocytic nevus (also known as nevus cell aggregates) is the most common heterotopic phenomena involving the axillary lymph nodes, the presence of benign epithelial inclusion cysts in axillary lymph nodes is a rare but well-reported finding. Such documentation is in part due to assessment of sentinel lymph nodes in breast cancer becoming standard of care. These epithelial inclusion cysts offer a diagnostic pitfall in evaluation of sentinel lymph node in the setting of breast carcinoma. They also complicate assessment of sentinel lymph node during intraoperative frozen sections analysis. Case Report: We report a case of co-existent of benign squamous-type and glandular-type epithelial inclusions cysts in 2 sentinel lymph nodes in a patient with grade III invasive ductal carcinoma involving the left breast. There have been at least 4 cases reported in literature in which benign epithelial inclusion cysts in sentinel lymph nodes were first mistakenly diagnosed as metastatic carcinoma both during intraoperative frozen section analysis and during review of permanent sections. The missed diagnosis could potentially occur intraoperatively during frozen section sentinel lymph node analysis secondarily due to lack of availability of the primary tumor for comparison and inability to use immunohistochemical stains. Conclusions: Pathologists should be aware of this pitfall especially in frozen section analysis of sentinel lymph node to avoid misdiagnosis and its associated potential grave consequences

Metastatic Signet Ring Cell Carcinoma Presenting as a Thyroid Nodule: Report of a Case With Fine-Needle Aspiration Cytology

Metastatic carcinomas to the thyroid are quite rare in daily cytology practice. However, when present they may produce a diagnostic dilemma, particularly when they share some morphologic similarities with primary thyroid lesions and when occurring in patients with occult malignant history. Herein, we report a case of metastatic gastric signet ring cell carcinoma to the thyroid. Our patient presented with an isolated right thyroid nodule, which was clinically considered to be a primary thyroid neoplasm. Fine-needle aspiration (FNA) cytology of the nodule revealed a cellular specimen with cohesive fragments and scattered individual neoplastic cells. The neoplastic cells had enlarged nuclei, fine chromatin, and inconspicuous nucleoli. Nuclear crowding, molding, and grooving were prominent. Intranuclear inclusion-like clearance was identified. Some tumor cells also had eccentric nuclei, creating a signet ring cell appearance. The colloid was scant. These cytological features may be seen in cases of papillary thyroid carcinoma or signet ring cell follicular adenoma; however, the presence of the signet ring cells is unusual in primary thyroid lesions and raises the possibility of a metastatic lesion to the thyroid. In our case, the tumor cells were positive for AE1/AE3, mucicarmine, and periodic acid-Schiff, but negative for thyroglobulin and thyroid transcription factor-1. The patient was also found to have a 3.7-cm mass in the distal esophagus/proximal stomach. Biopsy of this mass showed an invasive signet ring cell carcinoma. The purpose of our study is to discuss the cytological features and the differential diagnosis of this unusual thyroid FNA case