Transudative pleural effusion of malignant etiology: Rare but real

Abstract

A 62-year-old female presented to the emergency room with one-month history of epigastric abdominal pain, nausea and vomiting. She endorsed progressive dyspnea over two weeks. CT of the abdomen demonstrated bilateral pleural effusions and pancreatic inflammation, so the working diagnosis was pancreatitis. A diagnostic thoracentesis was performed and the pleural fluid analysis was classified as transudate by Light's criteria. Given the atypical features in history and concern for malignancy, fluid was sent for cytological examination and immunohistochemistry which suggested a mucinous malignancy. EGD revealed poorly differentiated signet ring cell adenocarcinoma of stomach. Patient underwent placement of indwelling pleural catheters for symptomatic improvement and was discharged to hospice. The decision whether to routinely send transudative effusions for cytological evaluation remains controversial. This case demonstrates the importance of using clinical judgement to guide that decision.

Catéter pleural permanente una opción para el manejo del derrame pleural maligno

“…Sin embargo, la acumulación de un trasudado puede ocurrir en el compromiso tumoral de la pleura y se considera como un falso trasudado (16). Por lo tanto, es necesario procesar citología en todos los casos en que se considere malignidad como posible diagnóstico (17).…”

“…Su presencia implica pronóstico, tratándose de compromiso pleural a distancia por un tumor primario (siembra hematógena o linfática) o compromiso pleural por vecindad (extensión local o cavitación) (19). Como ya se describió, en la mayoría de los casos el derrame es un exudado linfocitario, aunque algunos trasudados pueden ser neoplásicos (17). Algunas características pueden sugerir malignidad; estas son: el líquido hemorrágico, la duración mayor a un mes, la ausencia de fiebre y los hallazgos tomográficos tales como pleura nodular, engrosada con realce por el medio de contraste (21)…”

Quantitative INTERSPECIMEN variability during biphasic pleural fluid cytological sampling in adenocarcinoma effusions

“…Malignant pleural effusion is the most common type of an exudative pleural effusion ranging from 72% to 79% of all cases. In extremely rare cases, a transudative effusion can ultimately be proven to be malignant . Adenocarcinoma is considered the most common subtype of lung carcinoma associated with malignant pleural effusion …”

“…In extremely rare cases, a transudative effusion can ultimately be proven to be malignant. 3,4 Adenocarcinoma is considered the most common subtype of lung carcinoma associated with malignant pleural effusion. 5 .…”