Unexpected Histopathological Diagnosis of Placental Transmogrification of the Lung after Bullectomy for Recurrent Spontaneous Pneumothorax: A Case Report and Literature Review

Abstract

We report a 33-year-old man who presented with recurrent right pneumothorax. Computed tomography (CT) showed the presence of a large bulla with a maximum diameter of 8 cm in the right middle lobe; he subsequently underwent bullectomy. Histopathology revealed that pulmonary parenchyma adjacent to the bulla represented nodular proliferation of clear cells characterized by a papillary structure resembling placental chorionic villi. Immunohistochemically, clear cells were positive for CD10, suggesting placental transmogrification of the lung (PTL). We reviewed 36 surgical cases of PTL, and only 2 cases (5.6%), including our case, were operated for spontaneous pneumothorax. Bullous lesions secondary to PTL tend to appear as unilateral large cystic masses in non-upper lobes, which is atypical for primary spontaneous pneumothorax (PSP). Although PTL is considered a very rare cause of secondary pneumothorax, we must carefully differentiate this condition.

Pulmonary placental transmogrification: a difficult pattern in differential diagnosis of pulmonary hamartomas from a tertiary care hospital in Turkey

“…This increase in the epithelial clefting may explain the papillary pattern of PT. Although it was frequently noted in PT cases associated with bullous emphysema in the literature [12,16,17], any lymphatic or vascular channel formation and dilation were not observed in our sections. Therefore, the origin and pathogenesis of PT associated with the pulmonary hamartomas may differ from PT associated with bullous emphysema [9,10].…”

“…Until now, approximately 50 reported cases of pulmonary PT in the English literature [11][12][13][14][15][16][17][18][19][20][21][22][23]. To our best knowledge, there is no study reporting that PT was histopathologically diagnosed in a hamartoma, and presented more than one case in a single center.…”

A Case of Placental Transmogrification of Bilateral Lung

“…Therefore, PT can also be considered as a morphologic expression of multiple pathologic conditions, rather than a single entity. Patients’ ages ranged from 14 to 75 years, with a mean of 45 years 2,6,7 . The reported cases have an obvious predominance among males (male-to-female ratio, 4.0) and smokers 2 .…”

“…He coined the term “placental transmogrification” for the lesion because of its pathologic resemblance to the papillary structures of the placental villi 1 . Since then, approximately 40 surgical cases had been reported in the literature as of 2019 2 . PT of the lung usually involves the lobar level in one lung, and approximately one-quarter of the reported cases were asymptomatic 2 .…”

“…Since then, approximately 40 surgical cases had been reported in the literature as of 2019 2 . PT of the lung usually involves the lobar level in one lung, and approximately one-quarter of the reported cases were asymptomatic 2 . However, many reported cases showed respiratory symptoms due to giant bullae or pneumothorax, thus requiring surgical resection.…”