PRIMARY MUCINOUS ADENOCARCINOMA OF THE LUNG WITH SIGNET-RING CELLS AND ALK REARRANGEMENT: A CASE REPORT

Abstract

TYPE: Case Report TOPIC: Lung Pathology INTRODUCTION: The presence of malignant signet-ring cells is more commonly seen in the adenocarcinomas, particularly those of the gastrointestinal tract and breast. In a study with 24,171 patients with signet-ring cell carcinoma (SRCC), it was found that only 3.1% of the cases have a primary pulmonary origin, making the study of SRCC of the lung restricted to reports and case series. CASE PRESENTATION: We present the case of a 70-year-old patient with a history of retroperitoneal liposarcoma and papillary thyroid carcinoma in whom a primary pulmonary adenocarcinoma of mucinous pattern with signet-ring cells and ALK rearrangement was diagnosed. DISCUSSION: The World Heart Organization (WHO) had included the SRCC subtype. However, since 2015 WHO classification, it is recognized only as cytologic features rather than primary histologic subtype. The incidence of primary SRCC of the lung is between 0.14 to 1.9% of all lung tumors. The differences in incidence rates lie in the definition since clear diagnostic criteria have not been established. Its presentation is slightly more common in men (52.7%) and Caucasian patients (82.2%), with a mean overall survival duration of 8 months. Patients presenting with the EML4-ALK fusion protein have unique pathological and physiological characteristics. Several reports have shown that it predominates in a young female population with adenocarcinoma and without exposure to tobacco. However, these are not consistent data in all studies. CONCLUSIONS: Lung cancer has a very heterogeneous presentation. We emphasize the importance of approaching these patients with histopathological, immunohistochemical, and molecular biology studies. DISCLOSURE: Nothing to declare. KEYWORD: pulmonary signet ring cell carcinoma