J Korean Med Sci 2004; 19: 901-3 ISSN 1011-8934 Copyright The Korean Academy of Medical Sciences Pulmonary Metastases of Uterine Endometrial Stromal Sarcoma: Diffuse Micronodular and Ground Glass Opacities : A Case Report Pulmonary metastases of uterine endometrial stromal sarcoma (ESS) are uncom- mon. The patterns of uterine ESS metastasis to the lung are multiple pulmonary nodules, single nodule, or cystic lesions. Pulmonary intraalveolar micronodular metas- tases of uterine ESS are unusual and have not been reported. We experienced a case of metastatic uterine ESS presenting as pulmonary diffuse micronodules with ground glass opacities on chest computed tomography of a 37-yr-old woman who previously underwent hysterectomy due to low grade ESS of the uterus four years ago. The histologic findings of video assisted thoracotomy biopsy showed numer- ous intraalveolar polypoid micronodules protruding from the alveolar septums. All tumor nodules were composed of short spindle cells arranged in ill-defined whorls, and nuclear feature and sparse cytoplasm were seen in uterine ESS. Immunohis- tochemically, these cells showed strong nuclear staining for estrogen receptor and progesterone receptor, and diffuse cytoplasmic staining for CD10. Key Words : Sarcoma, Endometrial Stromal; Neoplasm Metastasis; Lung Neoplasms Gou Young Kim, Chang Ohk Sung, Joungho Han, Joon Oh Park*, Kyung Soo Lee Departments of Pathology, Division of Hematology/ Oncology, Departments of Internal Medicine*, and Radiology , Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea Received : 11 November 2003 Accepted : 26 December 2003 Address for correspondence Joungho Han, M.D. Department of Pathology, Sungkyunkwan University School of Medicine, Samsung Medical Center, 50 Ilwon-dong, Kangnam-gu, Seoul 135-710, Korea Tel : +82.2-3410-2765, Fax : +82.2-3410-0025 E-mail : jhhan@smc.samsung.co.kr INTRODUCTION Distant metastases of uterine endometrial stromal sarco- ma (ESS) are uncommon. The most commonly affected site is the lung, with a reported incidence ranging from 7% to 28% (1). Multiple pulmonary nodules are common patterns of metastases of uterine ESS. Unusual presentations included bilateral spontaneous pneumothoraces with predominantly cystic lesions (2-4). Metastatic uterine ESS presenting as a solitary lung nodule is also unusual and only a few cases were documented histologically (1, 5). A case of bilateral reticulo- nodular infiltrates corresponding to a lymphangitic growth pattern was documented (1). We experienced a case of pul- monary metastases of uterine ESS that presented intraalveo- lar micronodules, which is a rare pattern of metastasis not described in English literature. CASE REPORT A 37-yr-old woman with increased extent of small random micronodules and ground glass opacities (GGO) in both lungs with dyspnea visited the hospital. She had been diagnosed with ESS in the uterus which had been removed due to post- partum bleeding 4 yr ago. One year later, both of her ovaries and vaginal stump were removed due to the recurred uterine 901 ESS. At that time, chest computed tomography (CT) showed miliary pattern of micronodules in both lung fields with symp- tom of dyspnea American Thoracic Society (ATS) grade I. Chemotherapy with Southwest Oncology Group (SWOG) protocol and ifosphamide were performed. During the 3 yr follow-up period, no significant change was found in pul- monary micronodular densities, but occasionally, GGO was found on chest CT with symptoms of dyspnea ATS grade II and fever (Fig. 1). These GGO and her symptoms improved after corticosteroid therapy and the nature of GGO was clini- cally regarded as alveolar hemorrhage or intraalveolar fibroblas- tic polyps. Video assisted thoracotomy biopsy was performed to evaluate the pulmonary micronodules and GGO. Under gross examination, numerous round or ovoid gray white sand- like granular lesions were apparent. Histologic sections showed numerous micronodules in the alveolar spaces (Fig. 2). These nodules consisted of short spindle cells arranged in ill-defined whorls and the neoplastic cells had bland nuclear features and eosinophilic cytoplasm (Fig. 3). Mitotic figures were less than 2 per 10 high power fields. The histologic features of the lung nodules were identical to that of low grade uterine ESS obtained from hysterectomy specimen. Immunohistochem- ically, these neoplastic cells showed strong nuclear staining for estrogen receptor (Novocastra, Newcastle, U.K., 1:100 dilution) (Fig. 3, inset) and progesterone receptor (Novocas- tra, 1:40 dilution), and diffuse cytoplasmic staining for CD10