Metastatic urothelial carcinoma with signet ring features: Cytomorphologic findings in abdominal paracentesis

Pleural fluid metastasis of plasmacytoid urothelial carcinoma in comparison to micropapillary and conventional high-grade urothelial carcinoma: Cytologic and immuonohistochemical findings

Plasmacytoid urothelial carcinoma (PUC) is a rare but clinically aggressive variant of high-grade urothelial carcinoma (HGUC). Cytological features include single plasmacytoid neoplastic cells with N:C ratio around 0.5, eccentric nuclei, nuclear hyperchromasia, irregular nuclear membrane, and vacuolated cytoplasm. Micropapillary urothelial carcinoma (MPUC) is another clinically aggressive variant of HGUC that shares some overlapping features of PUC. The diagnosis of these two aggressive variants in pleural effusions can be challenging due to features mimicking adenocarcinoma, unusual immunochemistry profile, and confusion with differential diagnoses, especially when pertinent clinical information is unavailable. We present report on one case each of pleural fluid metastasis of PUC and MPUC respectively, and compare the findings with that of a metastatic conventional HGUC originally thought to be metastatic adenocarcinoma. The diagnosis of PUC was confirmed with immunohistochemical studies showing expression for cytokeratin, GATA-3, uroplakin II, and CD138, diminished or loss of E-cadherin membranous expression, negative expression for p63, p53, Epicam-BerEP4, Epicam-MOC31, and p120. The diagnosis of MPUC was confirmed with immunostain profile similar to that of PUC except positive stain for E-cadherin, p120, and p53. The diagnosis of HGUC was confirmed with immunohistochemical studies showing expression for cytokeratin, GATA-3, uroplakin II, p63, Epicam-BerEP4 (focal weak), and Epicam-MOC31. Our cases of metastatic urothelial carcinoma showed features mimicking adenocarcinoma and others, especially the MPUC and HGUC were diagnosed without prior tissue diagnosis of urothelial carcinoma. This report emphasizes the cytohistological and immunohistochemical details of urothelial carcinoma involving effusion fluid and discusses potential pitfalls in diagnosis.

Metastatic genitourinary cancer diagnosed by body fluid cytology: clinicopathologic and cytomorphologic correlation

INTRODUCTION

Malignant effusions secondary to genitourinary cancers constitute less than 5% of metastatic malignancies. Because of their rarity, definitive cytodiagnosis may be challenging. Our study aims to examine the incidence of malignant fluids secondary to genitourinary cancers in our institution, and to characterize their clinicopathologic and cytomorphologic features.

METHODS

A search of our database was undertaken for all body fluids reviewed from January 2003 through April 2014 at our institution.

RESULTS

During this 11.3-year study period, our search revealed 8255 body fluids. Of these, 1341 (16.2%) were malignant with only 15 (0.2%) due to a genitourinary primary, constituting a mere 1.1% of all malignant fluids. Eight cases (53%) were urothelial carcinomas, 6 (40%) were renal cell carcinomas, and 1 was a bladder leiomyosarcoma (7%). No prostate cancers were found. Seven (47%) involved the pleura, 6 (40%) were in the peritoneum, and 2 (13%) were in the cerebrospinal fluid (CSF). None were detected in the pericardium. Genitourinary metastases comprised 1.9% of peritoneal, 0.8% of pleural, 1.9% of CSF malignant fluids.

CONCLUSION

Metastatic genitourinary cancers in body fluids are rare, comprising only 0.2% of all fluids and 1.1% of all malignancies. The cytomorphologic features of metastatic urothelial and renal cell carcinoma, although similar to those described in the literature, are nonspecific. To our knowledge, this is the first reported case of metastatic bladder leiomyosarcoma in ascites diagnosed by effusion cytology. Because leiomyosarcoma in body fluids can demonstrate epithelioid features and cohesiveness, it may be confused with metastatic carcinomas.

Follicular thyroid carcinoma with signet ring cell morphology: fine-needle aspiration cytology, histopathology, and immunohistochemistry

Thyroid follicular neoplasms with signet ring cell morphology represent a challenging cytological and histopathologic diagnosis. The low frequency of these neoplasms and their broad differential diagnosis contribute to this difficult scenario. Here, we present an exceptionally rare case of thyroid follicular carcinoma with signet ring cell morphology in a 62-year-old female. We analyze the characteristics in fine-needle aspiration cytology, histopathology, and immunohistochemistry and compare our results in a discussion with previous literature reports.

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.