Cancer Masking as a Parapneumonic Effusion

Abstract

SESSION TITLE: Lung Cancer 2 SESSION TYPE: Affiliate Case Report Slide PRESENTED ON: Tuesday, October 31, 2017 at 07:30 AM - 08:30 AM INTRODUCTION: Pleural effusions often present a diagnostic dilemma. Light’s criteria has helped to narrow the focus but still may leave a broad differential. Here we present a case of a pleural effusion masked as a parapneumonic effusion but ultimately found to be secondary to a pleural based adenocarcinoma. CASE PRESENTATION: 67 yo M with COPD presented to the ED with c/o dyspnea, cough, f/c. His WBC was 23.7. CTA of chest performed showed a loculated right pleural effusion and mildly enlarged subcarinal lymph node. He was started on ceftriaxone/minocycline and admitted to the hospital. Thoracic US showed no evidence of loculations/septations. Thoracentesis removed 1.5L of serosangious fluid with pH of 7.35; exudative by Light’s criteria and presumed due to clinic context and lab findings to be a parapneumonic effusion. One week later patient presented to clinic with complaint of dyspnea. CXR showed re-accumulation of right sided pleural effusion and thoracentesis was performed, again removing 1.5L of serosanginous fluid. Culture remained negative, however cytology ultimately was reported as “Suspicious for malignancy.” Seven days later patient re-presented to clinic with increasing dyspnea, CXR showed reaccumulation of right sided effusion, and thoracentesis was performed, cytology resent and was negative. Chest CT was performed immediately after thoracentesis and revealed; resolution of the effusion, a mildly enlarged subcarinal LN but no mass. Six days later, patient had increasing dyspnea and recurrent right pleural effusion. Chest tube was placed and cytology re-sent, which remained negative. CT surgery performed VATS/pleural biopsy revealing pleural based poorly differentiated adenocarcinoma. PET scan showed diffusely enhancing pleura in the right lung with no dominant mass. DISCUSSION: Bloody pleural effusions are most commonly due to malignancy (47%), post-traumatic (12%), or parapneumonic (10%). Our patient had multiple signs/symptoms suggestive of pneumonia complicated by a parapneumonic effusion including; elevated WBC, acute onset, fevers, and cough. However, given the recurrence, malignancy rose higher on the differential. Interestingly, the patient had no dominant mass and ended up having the rare diagnosis of pleural adenocarcinoma. CONCLUSIONS: Recurrent effusions should suggest an alternate diagnosis and therefore workup should be broadened. Reference #1: Vilenna, V. et al. “Clinical Implications of Appearence of Pleural Fluid at Thoracentesis” Chest. 2004 Jan;125(1):156-9. DISCLOSURE: The following authors have nothing to disclose: Amit Bharara, Rebecca Potfay No Product/Research Disclosure Information