Rationale: Placental transmogrification of the lung is a very rare lesion which was characterized by the presence of papillae resembling placental villi. Its pathogenesis still remains unclear. Some authors think that this lesion is congenital and related to hamartoma, and others advocate it is secondary change after emphysema. So far, the majority of reported cases manifested as bullous lesions, to our knowledge , only two cases presented as a solitary nodule.
Patient concerns: Herein, we report the third case presenting as a small nodule in a 49-year-old male. Chest computed tomography revealed a nodular shadow measuring 2.6 × 1.2 cm in the right lower lobe of the lung. Histologically, the tumor composed of papillary structures covered by cuboidal pneumocytes and bland clear cells and abundant capillaries in the stroma.
Diagnosis: The lesion was diagnosed as a placental transmogrification of the lung.
Intervention: The patient then underwent wedge resection in our hospital.
Outcomes: The postoperative course was uneventful.
Lessons: The patient had a history of traffic accident half a year before the nodule was detected. This prompts placental transmogrification of the lung may at least partially represent a acquired malformation. The present case aims to raise a new suggestion for its possible nature. In our opinion, PT may simply represent a benign morphologic change rather than an independent disease. It may be encountered in both congenital and secondary lesions.