Florid cystic endosalpingiosis of the spleen

Abstract

A case of endosalpingiosis appearing as a huge multilocular cyst in the spleen of a 31-year-old woman is reported. The cystic lumens were smooth, and lined by fallopian tubal epithelium containing ciliated and secretory cells. The epithelial lining showed neither atypia nor foci of papillary proliferation, with only 3-5% MIB-1 labeling index. The epithelial lining was histochemically negative for mucin, but positive for MUC1 and progesterone receptor. Despite the appearance of a tumor-like mass, it was diagnosed as florid cystic endosalpingiosis as there was a normal tube-like epithelium. Regarding etiology, it was considered to derive from the secondary müllerian system of the splenic capsule.

Müllerianosis: Four Developmental (Embryonic) Müllerian Diseases

“…Müllerian choristomas with 1 müllerian tissue-endosalpingiosis-have been found in the mediastinum, 10 spleen, 51 and cervix and uterus. 52…”

Florid cystic mullerianosis of the testis: new pathological entity originating from a peculiar Müllerian differentiation of the testicular vaginal mesothelium

“…8 The arrangement of cystic structures just beneath the mesothelium is also very similar to the entity described in women as florid cystic endosalpingiosis of the peritoneum. 9 Immunohistochemical studies reinforce the similarities between these two pathological entities, highlighting the expression of progesterone receptors in the epithelial cells, 10,11 and CD10 and progesterone receptor in the pericystic connective tissue.…”

A unique case of splenic tumor exhibiting a serous carcinoma phenotype

“… 9 Few cases of splenic endosalpingiosis have been reported in the literature. 10 – 12 According to some reports, mesothelial cells have the potential to differentiate into fallopian tube-like epithelium, and splenic endosalpingiosis arises from the invaginated splenic capsule or peritoneum. 6 , 10 , 12 Another hypothesis is that aberrant remnants of the proximal portion of the müllerian ducts develop into fallopian tube-like epithelium.…”

“… 10 – 12 According to some reports, mesothelial cells have the potential to differentiate into fallopian tube-like epithelium, and splenic endosalpingiosis arises from the invaginated splenic capsule or peritoneum. 6 , 10 , 12 Another hypothesis is that aberrant remnants of the proximal portion of the müllerian ducts develop into fallopian tube-like epithelium. 9 , 10 The term “secondary müllerian system” is used to explain these theories, 9 , 10 but the mechanism remains unproven.…”