A 38-year-old woman presents with dyspnea and general malaise. Diagnostic imaging revealed the presence of multiple bilateral cystic and nodular lesions in her lung.
Correct Answer: B. Lymphangioleiomyomatosis (LAM)
LAM is an unusual condition most commonly seen in women in their 30s and 40s. The process commonly involves both lungs and presents as cystic and nodular lesions. Microscopically, LAM can be easily misdiagnosed as emphysema; however, the presence of focal areas of smooth muscle with clear cells helps in the diagnosis. In addition, immunohistochemical studies may aid in the final interpretation, with the use of muscle-specific actin, CD34, and HMB45, which often are positive in the areas of muscle proliferation. In more recent years, LAM and clear cell “sugar” tumor of the lung have been grouped into a family of tumors under the PEComa (perivascular epithelioid cell tumors) designation. However, for practical purposes, it is best to designate these pulmonary lesions with their original name in order to avoid confusion.