Ectopic Cushing Syndrome in Adenocarcinoma of the Lung: Case Report and Literature Review

Abstract

Paraneoplastic syndromes are rare disorders that occur with many types of tumors. Ectopic cushing syndrome (ECS) is the second most common paraneoplastic syndrome that is only seen in 1-5% of all small cell lung cancers (SCLC), with limited papers reporting this syndrome since it was first described by Brown in 1928 or in carcinoid tumors. It is also found to be associated to a lesser extent with pheochromocytoma, thymic tumors, pancreatic carcinoma, and anaplastic thyroid carcinoma. While lung adenocarcinoma is the most common histological type of lung neoplasms, it is seldom associated with Cushing syndrome. In this article, we describe a patient who initially presented with Cushing syndrome and found to have adenocarcinoma of the lung.

Keywords: adenocarcinoma; ectopic cushing’s syndrome; paraneoplastic syndromes.

Figure 1. Chest radiograph demonstrated a 3 cm right upper lobe mass above the minor fissure (blue arrow) with possible infiltrative process extending toward the right hilum and prominent right hilum and right paratracheal soft tissues.

Figure 2. Computed tomography (CT) of the chest without contrast shows a speculated 2.7 cm lesion in the right upper lobe (red arrow) with right hilar and paratracheal lymphadenopathy measuring 3.8 cm and 4.7 x 3.7 cm, respectively.

Figure 3. Histopathology of the right upper lobe lung mass was performed and showed pulmonary adenocarcinoma, moderately to poorly differentiated (left slide). The tumor cells were positive for CK7, TTF-1, and Napsin A (weak and focal), and negative for CK20 or p40 (middle slide). Mucin stain was positive (right slide).