[Pulmonary lymphangioleiomyomatosis (LAM). Diagnostic usefulness of immunohistochemical markers]

Lymphangioleiomyomatosis (LAM) is a rare disease of unknown cause affecting the lungs of female patients. Although clinical and radiological findings may suggest LAM, a firm diagnosis is usually made after lung biopsy. Cases of LAM (histochemical diagnosis) or "suggestive of LAM" at the "12 of October" Hospital are reviewed. We applied a battery of immunohistochemical tests not used to date--involving estrogen, progesterone, desmin and HMB45 receptors--that allowed us to classify specimens as having either LAM lesions or lesions with non-LAM muscle proliferation. Smooth muscle proliferation in LAM is a distinct phenotype, such that diagnosis is facilitated by analyzing for immunohistochemical markers such as HMB45. This marker can be detected on formalin-fixed paraffin-embedded sheets in specimens obtained by either open lung or transbronchial biopsy.