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A1574 - Benign Metastasizing Leiomyoma Presenting with Lymphangitic Carcinomatosis
Author Block: A. Shioleno, A. Wu; Division of Pulmonary Medicine, New York Presbyterian Weill Cornell, New York, NY, United States.
Benign metastasizing leiomyoma is a rare entity that typically presents in pre-menopausal women with a history of uterine fibroids. Most present with discrete asymptomatic nodules, but rare cases of miliary disease have been reported. There are no strict guidelines for managing these patients, especially those with advanced pulmonary disease.
This is a case of a healthy 38 year old female who presented with three weeks of dyspnea and dry cough. A review of systems was negative except for abnormal uterine bleeding two months prior. She was diagnosed with a benign fibroid on ultrasound and initiated on oral contraception pills containing estrogen. Her family history was negative for pulmonary disease or malignancy. She denied foreign travel, sick contacts, or mold exposure but had recently purchased chickens. She presented to an outside hospital where she was hypoxemic to 84% on room air. A CT Chest with PE protocol showed bilateral upper and lower lobe ground glass opacities with smooth interlobular septal thickening. She underwent a bronchoscopy with normal cellular differential and negative infectious work up. Given her chicken exposure, she was initiated on prednisone for empiric hypersensitivity pneumonitis treatment. Her auto-immune serologies, HIV, hypersensitivity panel and a TTE with bubble study were all negative. She presented to our hospital after failing to improve on two weeks of steroids. She underwent an open lung biopsy. Pathology revealed smooth muscle cell infiltration along the lymphatics forming innumerable nodules in an interstitial distribution along the visceral pleura and interlobular septa. The cells stained positive for SMA, Desmin, Estrogen and Progesterone but negative for HMB45 and A103. There was no necrosis seen and only mild atypia without mitosis. She was diagnosed with benign metastasizing leiomyoma.
This is the first case of benign metastasizing leiomyoma presenting as ground glass opacities with interlobular septal thickening mimicking lymphangitic carcinomatosis. The differential for abnormal smooth muscle cell proliferation in the lungs includes leiomyosarcoma and lymphangioleiomyomatosis. However, the negative HMB45 and A103 stains and the absence of cystic lung disease excluded lymphangioleiomyomatosis. The lack of mitosis and atypia were also inconsistent with a leiomyosarcoma. Given that her disease progressed dramatically on estrogen we started Letrozole for hormonal suppression. She improved initially but worsened again after three weeks. We decided to pursue a hysterectomy with bilateral salpingo-oophorectomy for complete hormonal suppression. Uterine pathology confirmed a benign fibroid. Three weeks later her dyspnea and hypoxemia had again improved on a six-minute walk test.