A Case of Micronodular Pneumocyte Hyperplasia Diagnosed through Surgical Resection

Case
Report

Yasushi Shintani, MD, PhD,¹ Mitsunori Ohta, MD, PhD,¹ Teruo Iwasaki, MD, PhD,¹ Naoki Ikeda, MD, PhD,¹ Emiko Tomita, MD, Teruaki Nagano, MD, PhD,² and Kunimitsu Kawahara, MD, PhD²

Micronodular pneumocyte hyperplasia (MNPH) is often associated with tuberous sclerosis complex and/or lymphangioleiomyomatosis. We present the case of a 45-year-old woman with MNPH without evidence of either. A preoperative high-resolution chest computed topographic scan demonstrated a ground-glass opacity 8 mm in diameter that revealed the possibility of atypical adenomatous hyperplasia (AAH) or bronchioloalveolar carcinoma (BAC). Therefore an S3 segmentectomy of the right lung was performed, and the specimens revealed the characteristic histological and immunohistological features of MNPH. Solitary MNPH is extremely rare and requires to be distinguished from AAH or BAC on a computed tomographic scan; therefore surgical resection may be required to definitely rule out malignancy. (Ann Thorac Cardiovasc Surg 2010; 16: 45-47)

Key words: micronodular pneumocyte hyperplasia, atypical adenomatous hyperplasia, ground-glass opacity

Departments of ¹Thoracic Surgery and ²Pathology, Osaka Prefectural Hospital Organization, Osaka Prefectural Medical Center for Respiratory and Allergic Disease, Habikino, Japan

Received December 2, 2008; accepted for publication January 23, 2009.
Address reprint requests to Yasushi Shintani, MD, PhD: Department of Thoracic Surgery, Osaka Prefectural Hospital Organization, Osaka Prefectural Medical Center for Respiratory and Allergic Disease, 3–7–1 Habikino, Osaka 583–8588, Japan.