Pulmonary dermoid cyst mimicking hydatid cyst: a case report with literature review.

Intrapulmonary dermoid cyst (mature cystic teratoma) is rare and may mimic common cystic lung diseases, particularly pulmonary hydatid disease. A 26-year-old woman presented with dyspnea and left-sided chest, shoulder, and neck pain. Computed tomography demonstrated a large complex cystic lesion in the left upper lobe with gas locules and associated pleural and pericardial effusions, initially suggesting a hydatid cyst. Video-assisted thoracoscopic excision revealed hair and heterogeneous cyst contents, and histopathology showed mature tissues from multiple germ layers with xanthogranulomatous inflammation, confirming a mature teratoma. The patient remained well at the 3-month follow-up. A focused review of eight reported cases of intrapulmonary teratoma showed heterogeneous presentations and recurrent preoperative diagnostic uncertainty. Intrapulmonary teratoma may present as a complex cystic lung lesion and can be mistaken for a hydatid cyst or a lung abscess.