Cystica indeterminata – A novel intriguing pelvic pathology in a 9-year-old girl

Intra-abdominal cystic lesions are commonly associated with visceral locations such as renal, hepatic, pancreatic, ovarian/adnexal, and mesenteric. Rarely, nonvisceral locations such as retroperitoneum, free intra-peritoneum, prevertebral space, and pelvis harbor cystic lesions. In almost all these lesions, radiology, histopathology, immunostaining, and serology markers are able to assign a definite origin and pathogenesis. Very rarely a clear diagnosis is not possible, and these lesions have been designated as “indeterminate” lesions. We report the first case of “cystica indeterminata” with completely obscure origin and histopathogenesis in a 9-year-old female child. Clinical, radiological, seromarkers, histopathology, related differentials, and pathogenesis have been discussed. We hypothesize that aborted organogenesis or acquired degenerative/involutory changes may lead to such indeterminate lesions.