Case Report This work is licensed under the Creative Commons Attribution 4.0 License. Published by Pacifc Group of e-Journals (PaGe) Retroperitoneal Teratoma in An Infant: Case Report Introduction Teratoma is a term derived from Greek words teratos/ teras, meaning “monster,” and onkoma/oma, meaning a swelling, tumour or neoplasm. A teratoma is a true tumour or neoplasm having multiple tissues of kinds foreign to the parts in which it arises. The tumour consists of the tissues that arise from embryonic ectoderm, mesoderm and endoderm. Common locations of teratomas in children are sacroccocygeal, gonadal, mediastinal, and retroperitoneal [1-5] . Teratomas may also occur at very unusual locations. Intra-peritoneal teratomas arise from mesentery and mesocolon, gastric teratoma, spinal teratoma, teratoma occurring at cervical region. Intra-cranial teratomas occur at medulla oblongata. Teratomas may arise from liver and kidney as well [6-10] . Here, we present a case of retroperitoneal teratoma in a one year old female child. Case Report One year old female infant presented with left abdominal mass since 7 months of age. Clinical examination revealed a solitary, non-tender, soft to frm, irregular cystic mass, occupying her left abdominal region. An abdominopelvic computerized tomography scan revealed a 13.5 cm x 10.4 cm x 9.8 cm-large cystic lesion with calcifcations/ bony elements scattered in it. The urinary bladder, uterus and ovaries were normal for the age. The preoperative radiological diagnosis was retroperitoneal teratoma. At laparotomy, the excised retroperitoneal mass was partly encapsulated, greyish white to greyish brown tumorous lesion with the smooth surface, and the pedunculated extension of the tumour at one focus weighing 584gms, and measuring lateral medial 14.5x11.0x8.5cm. The consistency was cystic to soft in multiple foci [Fig 1]. On sectioning through the tumour proper, a solid cystic tumorous lesion with the cystic component signifcantly located towards the periphery, a few of them containing brownish altered chocolate like fuid was noticed. The rest contained clear or mucinous content within. The solid portion had a greyish white slimy appearance mostly without apparent evidence of necrosis. There was condensation of the capsule towards the periphery which appeared thinned out. On sectioning the pedunculated extension of the tumour, similar appearance of predominantly solid confguration is noticed. Areas with tan-white, soft and lobulated, with multiple islands of cartilage and bony elements were also noticed. There was no grossly recognizable ovary, fallopian tube, placenta or umbilical cord. Histopathological examination revealed a neoplasm containing a conglomerate of derivatives of ecto, endo, and mesoderm is variable proportion, mature in nature. Extensive areas of mature adipocytes (lipid tissue), well defned scattered foci of mature hyaline cartilage, smooth muscle and skeletal muscle component, cystic glandular structures are discernible [Fig 2]. Large cystic areas lined by colonic mucosal epithelium with underlying smooth muscle component and lymphoid element with well- defned germinal centers were noted. Scattered foci of mature bone containing marrow element within was also observed [Fig 3]. Elsewhere, gland like structures lined by ciliated columnar mucosa without any atypia was seen. There was no apparent evidence of primitive neuroepithelial tissue, immature hyaline cartilage or formation of rosettes. No apparent evidence of endodermal sinus tumour component was observed. Elsewhere, scattered nerve bundles, a few exhibiting mature ganglion cells was noticed. There was no evidence of necrosis, mitotic activity, atypia or haemorrhage. Barani Karikalan 1 * and Thanikachalam Meenakshi Pasupati 2 1 Dept of Pathology; Perdana University, Jalan Maeps Perdana, Serdang, Selangor, Malaysia 2 Dept of Histopathology; Clinipath Pathology laboratory, Malaysia ABSTRACT Common location of teratomas in children are sacrococcygeal, gonadal, mediastinal and retroperitoneal, but teratomas may also occur at very unusual locations. A one-year-old girl presented with a large swelling at her left abdomen. Clinical examination revealed a solitary, non-tender, soft to frm, irregular cystic mass, occupying her left abdominal region. Computed Tomography (CT) scan fnding was consistent with retroperitoneal teratoma. Complete surgical excision of the tumour was done without any difculties. Histology of the excised tumour was conclusive of mature cystic teratoma. Keywords: Children; Infant; Surgical Therapy; Teratoma; Retroperitoneal Tumour DOI: 10.21276/APALM.2331