Signet Ring Cell Carcinoma of the Colon Mistaken for Lung Disease

Abstract

Signet ring cell carcinoma of the colon is an extremely rare subtype of mucinous adenocarcinoma, comprising of less than one percent of all tumors of the colon and rectum. Because of its rare and aggressive nature, its presentation is usually late its course. CASE PRESENTATION: We present the case of a 62-year-old male with a history of colon cancer treated with surgical resection and chemotherapy one year prior to presentation. He had no radiographic evidence of disease during follow up with his oncologist four months prior to presentation. He presented to the hospital with complaints of shortness of breath and cough. CT angiogram of the chest revealed diffuse patchy consolidative airspace disease with bilateral adenopathy, suspicious for multifocal pneumonia (Figure 1). The patient was started on broad spectrum antibiotics and underwent diagnostic bronchoscopy, with no significant luminal abnormalities reported. The cell count from the bronchoalveolar lavage (BAL) and cytology were both unremarkable, along with all infectious, inflammatory, and rheumatologic workups. Given lack of improvement, the patient was treated with high dose systemic corticosteroids and completed a 7-day course of broad-spectrum antibiotics. Despite therapy, his respiratory status continued to decline, necessitating high flow nasal cannula and intermittent noninvasive ventilation. A subsequent CT of the abdomen showed new retroperitoneal adenopathy. He then underwent Endobronchial Ultrasound and bronchoscopy with biopsies of two new endobronchial lesions and areas of abnormal appearing mucosa. Lymph node sampling was completed at stations 11L, 7, and 11R, along with BAL of the right middle lobe. Following this procedure, our patient was started on pulse dose steroids. On the third day of this therapy, his respiratory status further declined, requiring intubation and mechanical ventilation. He demonstrated severely reduced compliance and was difficult to ventilate despite multiple modes of mechanical ventilation. He clinically deteriorated with progressive respiratory acidosis and vasopressor refractory shock. He subsequently arrested and expired shortly thereafter on hospital day 24.