Unexpected endometrial malacoplakia related to abortion and placental rests retention: a case report

BACKGROUND: Malacoplakia is a rare chronic inflammatory disease. The name derives from the Greek “μαλακός” meaning “soft” and “πλάξ” meaning “plaque”, describing its usual macroscopic presentation as a friable yellow soft plaque. It was first described by von Hansemann in 1901 and by Michaelis and Gutmann in 1902. The urinary system is the most commonly involved site. Female genital tract involvement is extremely rare. Treatment is prevalently based on antibiotics with surgical intervention sometimes necessary. Prognosis is usually good, but relapse may frequently occur. CASE PRESENTATION: This report illustrates the first case of endometrial malacoplakia in a 40 years-old patient who received endometrial curettage due to the retention of placental rests following an abortion. After conspicuous vaginal sero-hematic secretions, the patient received a further curettage. The histological examination did not show any retention of chorionic rests, but an endometrial and myometrial infiltration of histiocytes with large granular cytoplasm within a chronic inflammatory background. Immunoreactivity for CK-pool was negative, while CD68 immunostaining was strongly positive. CONCLUSIONS: Malacoplakia of endometrium is an extremely rare condition, with few cases reported in the whole international literature. In this paper, we present the first case associated to an abortion followed by endometrial curettage procedures. This rare disease should always be attentively examined, considering, among differential diagnoses, uterine neoplasms or physiological conditions such as cumulus of foamy macrophages in the endometrium.