LAM histology

Cyst formation and proliferation of LAM cells represent key histologic findings (Figure 5). These cells are often reactive to HMB-45 antibody IHC staining.

In less straightforward cases, transbronchial, thoracoscopic, or surgical biopsy is indicated. The primary histopathological abnormality in LAM is the proliferation of atypical smooth muscle-like cells (LAM cells) in numerous parts of the lung, including the alveoli, bronchi, interstitium, lymphatics, and pleural space. Immunohistochemical staining shows cell surface positivity for the human melanoma black 45 antigen.