Pulmonary lymphangioleiomyomatosis: a rare and challenging case report with unusual presentation of human melanoma black-45

Abstract

Lymphangioleiomyomatosis (LAM) is a very rare disease that generally affects young women of reproductive health group. It is characterized by abnormal proliferation of smooth muscle like cells (LAM cells) in the lungs (pulmonary LAM) and extrapulmonary sites (extrapulmonary LAM). Patients usually present with spontaneous pneumothorax, hemoptysis and progressive dyspnea. There is a poor awareness, knowledge and records about this disease making it a difficult diagnosis. Herein this report presents a case of pulmonary LAM in a 63 years old female with h/o dyspnea and chest pain. Her imaging studies showed fibrosis and nodular lesions in both lungs suggesting metastatic lesions. Later on, after a lung biopsy the diagnosis of lymphangioleiomyomatosis was given and immunohistochemical staining was positive for spinal muscular atrophy (SMA), CD34 and negative for human melanoma black-45 (HMB45). HMB45 negative PLAM is very rare with only few instances in the literature making it a difficult diagnosis. Our patient was given mTOR inhibitors along with supportive and conservative management and she responded well to the treatment. This rare cystic lung disease can be devastating as it causes progressive lung damage. Limited options in the management of PLAM makes early diagnosis as key and there is also a need for high index suspicion with cystic lung disease in women.