Endobronchial ultrasound-guided transbronchial needle aspiration diagnosis of mediastinal lymph node metastasis of mucinous adenocarcinoma: arborizing stromal meshwork fragments as a diagnostic clue.
Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) is a reliable and accurate method for the diagnosis of mediastinal metastases in patients with pulmonary and extrathoracic neoplasms. We report the cytopathologic findings of a case of metastatic signet-ring cell carcinoma with abundant extracellular mucin production in the mediastinal lymph nodes of a 41-year-old woman, who presented with nausea, abdominal pain, and weight loss. Imaging studies showed a renal mass, numerous lung nodules, and mediastinal and retroperitoneal lymphadenopathy. EBUS-TBNA of level 4R and 7 lymph nodes showed abundant, thick, "clean" mucus with entrapped ciliated bronchial cells, rare histiocytes, and fragments of cartilage. No neoplastic cells could be identified in Diff-Quik®-stained smears during the rapid on-site evaluation, but rare signet-ring cells were identified in the Papanicolaou-stained smears and cellblock sections. A distinctive feature of the aspirates was the presence of large branching (arborizing), "spidery" stromal fiber meshwork fragments. These stained metachromatically (magenta) with Romanowsky-type stains and cyanophilic to orangeophilic with Papanicolaou stains and showed occasional attached bland spindle cells, but had no capillary lumina or CD31-staining endothelial cells. The tumor cells were strongly and diffusely positive for CEA, CDX2, CK7, CK20, and MUC2, supporting the diagnosis of a metastatic signet-ring cell adenocarcinoma, most likely of gastrointestinal origin. We believe that the presence of the large spidery stromal fiber fragments is a useful clue to the presence of a mucinous neoplasm in EBUS-TBNA and allows the differentiation of the neoplastic mucus from contaminating endobronchial mucus.
Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, Minnesota.
Arbaz
A
Samad
Justin C
JC
Peltola
Mohi O
MO
Mitiek
Jose
J
Jessurun
J Carlos
JC
Manivel
Stefan E
SE
Pambuccian
D002288:Adenocarcinoma, Mucinous / Q000473:pathology*; D000328:Adult; D001999:Bronchoscopy; D018279:Carcinoma, Signet Ring Cell / Q000473:pathology*; D061765:Endoscopic Ultrasound-Guided Fine Needle Aspiration; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008479:Mediastinal Neoplasms / Q000473:pathology* / Q000556:secondary*; D017154:Stromal Cells / Q000473:pathology