Tumoral and pseusotumoral processes of the vagina in the pediatric population: A 26-YEAR retrospective study.

Background: Vaginal lesions are rare and of various types in children. Clinical presentation is generally undifferenciated. Histological examination is fundamental to ascertain the nature of the lesion. Regarding tumoral lesions, histological subtypes encountered are radically different from those seen in adults, dominated by stromal benign lesions.

Objective: The aim of this retrospective study was to describe characteristics and pathological aspects of pediatric vaginal lesions, diagnosed in a single pediatric experienced center.

Study Design: A database analysis was performed on all vaginal samples of patients under 18 years old received in a pediatric-specialized pathology laboratory of an academic hospital, over a 26-year period.

Results: Among 36 vaginal tissue samples reported, a total of 15 tumoral or pseudotumoral processes was recorded. Primitive malignant tumors included embryonal rhabdomyosarcoma (n = 3) and germ-cell tumors, yolk-sac type (n = 2). Benign tumoral or pseudotumoral processes included inflammatory stromal polyps (n = 8), epidermic cyst (n = 1), and benign Müllerian papilloma (n = 1).

Discussion: Over 15 primitive vaginal tumors, 1/3 was malignant with embryonal rhabdomyosarcoma being the most common. The remaining 2/3 specimens were benign, with stromal inflammatory lesions being the most commonly observed. Fibro-epithelial polyp is a debated entity, which covers a wide histological spectrum, with varying inflammation and stromal cellularity, raising sometimes the question of the differential diagnosis with rhabdomyosarcoma. Stromal cells morphology along with their immunohistochemical profile suggest their reactive myofibroblastic nature. Pseudotumoral inflammatory lesions display very similar histological findings with these entities. A common pathogenesis beginning with an inflammatory process, potentially accelerated by chronic traumatic factors, could be discussed.

Conclusion: We confirmed the rarity and the diversity of vaginal lesions in children. Vaginoscopy and biopsy sample should be systematic, given the non-specific presentation of tumoral processes. Myogenin immunostain must be systematic in case of vaginal polypoid mass, in order to rule out malignancy.