Primary renal teratoma: an important differential diagnosis in the evaluation of cystic renal masses in infants

Renal teratoma is an extremely rare condition and may create diagnostic confusion with teratoid nephroblastomas or retroperitoneal teratomas with secondary involvement of the kidney .We report a 35 day old female child presenting in paediatric surgery OPD with complaints of pain abdomen and abdominal distension.. On palpation, a lump was felt in the lower abdomen measuring around 5x4x3 cms and a diagnosis of multilocular cystic nephroma was given on CECT abdomen. The kidney mass was excised and on gross examination, multiloculated thin walled cysts containing both mucinous and serous fluid with some areas of hemorrhage were noted. Microscopy revealed areas of columnar epithelium, squamous epithelium with keratin deposition, cartilage, bone, fibrocollageneous tissue and muscle tissue. A diagnosis of mature primary renal teratoma was given. This case was presented as primary renal teratomas are extremely rare and must be considered in the differential diagnosis of infantile renal masses.