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Int J Clin Exp Pathol 2013;6(6):1138-1141

Case Report
Primary pure signet-ring cell carcinoma of the extrapulmonary left main bronchus: a
case report with an immunohistochemical study

Tadashi Terada

Department of Pathology, Shizuoka City Shimizu Hospital, Shimizu, Shizuoka, Japan

Received November 23, 2012; Accepted April 3, 2013; Epub May 15, 2013; Published June 1, 2013

Abstract: Although several case reports and series of primary signet-ring cell adenocarcinoma (SRCA) of the lung have been reported, primary
SRCA of the extrapulmonary main bronchus has not been reported. A 61-year-old man was found to have a tumor of the mediastinum of the left
pulmonary hilus on routine chest X-ray examination. A transbronchial endoscopy revealed an elevated tumor in the extrapulmonary left
bronchus near the tracheal bifurcation. Biopsy was taken from the bronchial lesion. It revealed pure typical SRCA. Histochemically,
Alcian-blue/PAS stain showed intracytoplasmic mucins. Immunohistochemically, the tumor cells were positive for cytokeratin (CK) AE1/3, CK
CAM5.2, CK7, CK18, CEA, EMA, CA19-9, Ki-67 (labeling=20%), p53, and MUC1. They were negative for CK34BE12, CK5/6, CK8, CK14, CK19,
CK20, p63, vimentin, TTF-1, CDX-2, MUC2, MUC5AC and MUC6. The pathological diagnosis of primary SRCA of the left main bronchus was
made. The patient died of carcinomatosis 18 months after the first presentation. In conclusion, the author reported the first case of primary
SRCA of the extrapulmonary left main bronchus near the tracheal bifurcation with an extensive immunohistochemical study. (IJCEP1211025).

Keywords: Bronchus, signet ring cell adenocarcinoma, histopathology, immunohistochemistry

Address correspondence to: Dr. Tadashi Terada, Department of Pathology, Shizuoka City Shimizu Hospital, Miyakami 1231 Shimizu-Ku,
Shizuoka 424-8636, Japan. Phone: +81-54-336-1111; Fax: +81-54-334-1173; E-mail: piyo0111jp@yahoo.co.jp