Clinicopathological and immunohistochemical analysis of epithelial-lined (true) cysts of the adrenal gland with proposal of a new histogenetic categorization

Observations on the origin of ovarian cortical inclusion cysts in women undergoing risk‐reducing salpingo‐oophorectomy

“…Interestingly, more than half the patients in their series were obese or overweight, although it was not specified if the two patients with epithelial cysts (the other cysts in the series were non‐epithelial) were included in this group. One of those cysts occurred in a 59‐year‐old male, supporting the metaplasia hypothesis over Müllerian implantation . Therefore, the notion that mesothelial OSE cells undergo tubal metaplasia is not far‐fetched; it is probably a common occurrence.…”

“…In the Müllerian tract, benign lesions and tumours can show heterologous metaplasia in the form of intestinal‐type mucinous cells expressing intestinal markers . A particularly interesting example of mesothelial to Müllerian metaplasia is that which occurs in epithelial adrenal cysts which are lined by mesothelial and/or FT‐like cells that express the associated markers calretinin/Wilms tumour 1 (WT1) and PAX8/ER, respectively . As adrenal glands do not naturally have any acinar structures with epithelial differentiation, the presence of epithelial lined cysts in these organs is thought to be a result of entrapped mesothelium during embryogenesis.…”

“…In one case report, a 31‐year‐old woman had an adrenal cyst lined by mesothelial and ciliated FT‐like cells where the Müllerian cells stained with PAX8, WT1, epithelial membrane antigen (EMA) and PR but not calretinin, while the mesothelial cells were positive for calretinin, WT1 and D2‐40 but also showed weak focal positivity for PAX8, EpCAM and EMA . Another case series by the same authors described two adrenal cysts lined by what appeared to be pure mesothelial cells lacking Müllerian differentiation which expressed both mesothelial (calretinin, WT1, D2‐40) and Müllerian (PAX8, ER and EMA) markers diffusely or focally in various combinations . Interestingly, more than half the patients in their series were obese or overweight, although it was not specified if the two patients with epithelial cysts (the other cysts in the series were non‐epithelial) were included in this group.…”

“…24 A particularly interesting example of mesothelial to M€ ullerian metaplasia is that which occurs in epithelial adrenal cysts which are lined by mesothelial and/ or FT-like cells that express the associated markers calretinin/Wilms tumour 1 (WT1) and PAX8/ER, respectively. 25,26 As adrenal glands do not naturally have any acinar structures with epithelial differentiation, the presence of epithelial lined cysts in these organs is thought to be a result of entrapped mesothelium during embryogenesis. In one case report, a 31-year-old woman had an adrenal cyst lined by mesothelial and ciliated FT-like cells where the M€ ullerian cells stained with PAX8, WT1, epithelial membrane antigen (EMA) and PR but not calretinin, while the mesothelial cells were positive for calretinin, WT1 and D2-40 but also showed weak focal positivity for PAX8, EpCAM and EMA.…”

“…26 Another case series by the same authors described two adrenal cysts lined by what appeared to be pure mesothelial cells lacking M€ ullerian differentiation which expressed both mesothelial (calretinin, WT1, D2-40) and M€ ullerian (PAX8, ER and EMA) markers diffusely or focally in various combinations. 25 Interestingly, more than half the patients in their series were obese or overweight, although it was not specified if the two patients with epithelial cysts (the other cysts in the series were non-epithelial) were included in this group. One of those cysts occurred in a 59-year-old male, supporting the metaplasia hypothesis over M€ ullerian implantation.…”