Thursday 21 August 2014
Placental transmogrification of the lung is a term introduced to describe a peculiar histologic pattern characterized by formation of placental villuslike structures in the lung parenchyma. It has been reported to occur in association with bullous emphysema and lipomatosis.
The histologic change consisted of an abundant myxoid or edematous fibroadipose stroma with a respiratory epithelial lining, resulting in papillary projections that resembled immature placental villi.
Epithelium lining the papillary projections was positive for TTF-1 (70%-90%) and Ki-67 (3%-5%). In contrast, stromal cells were negative for TTF-1 with only rare cells immunoreactive for Ki-67. A number of stromal spindle cells and occasional cells in epithelium were c-Kit immunoreactive; however, concurrent Leder stain demonstrated that these c-Kit-positive cells were mast cells and not stem cells.
The significance of numerous mast cells within stroma of placental transmogrification is unclear and their possible role in inducing stromal proliferation needs to be further evaluated.
pulmonary fibrochondromatous hamartomas
- Placental transmogrification has beenidentified in 6 of 38 cases of pulmonary fibrochondromatous hamartomas (11958661).
- Placental transmogrification is frequently associated with pulmonary fibrochondromatous hamartomas.
- It may be induced by or associated with a proliferation of lining epithelial components in the hamartomas.