Primary Carcinoid Tumor in a Retroperitoneal Teratoma in a Child.

Sir,

A 2-year-old male child presented elsewhere with an increasing, painless abdominal lump since infancy. A laparotomy was abandoned due to the large size of the lump and involvement of major vessels. The mass had further increased in size; he was discomfited on a liquid diet and had lost weight. He was pale and normotensive. A firm, nontender, lobulated mass occupied the entire abdomen [Figure 1a].

Figure 1

(a) The mass occupied the entire abdomen. (b) Contrast-enhanced computed tomography, coronal reconstruction with the inferior vena cava not visualized for most of its abdominal course. (c) The yellow thread on the mass traces the course of the deeply embedded inferior vena cava in its right half. (d) Photomicrograph showing the focus of carcinoid tumor with neoplastic cells arranged in ribbons and cords with thin intervening stroma (H and E, ×100). (e) Note their bland, vesicular nuclei, and powdery chromatin (H and E, ×400)

Contrast-enhanced computed tomography showed a 13 cm × 8 cm × 13 cm, well-defined, heterogeneous, solid, cystic retroperitoneal mass with echogenic areas and focal calcification displacing the liver, right kidney/adrenal, and bowel. The inferior vena cava (IVC) was not visualized in its course near the mass [Figure 1b]. Routine laboratory investigations including serum alphafetoprotein (2.47 ng/ml) and β-human chorionic gonadotropin (0.5 mIU/ml) were normal. A provisional diagnosis of a mature retroperitoneal teratoma with caval compression/encasement was made.

At laparotomy, the tumor was circumscribed but densely adherent to the aorta, superior mesenteric artery, and left renal artery. The right renal vein was splayed, and the IVC (infrahepatic region to the right renal vein) was encased in a deep groove at the extreme right of the mass [Figure 1c]. An accidental division of the grossly displaced IVC was recognized which was repaired without any hemodynamic disturbances. The postoperative Doppler evaluation confirmed normal patency and flow.

The tumor was nodulocystic and bosselated. The cut surface showed heterogenous areas: cysts – mucoid, pultaceous, and hemorrhagic; calcification; solid whitish; and fatty. Microscopic examination showed features of a mature cystic teratoma (skin, adipose tissue, mature glial tissue, skeletal muscle, mucous glands, pancreatic tissue, mature cartilage, choroid plexus, and cysts with pseudostratified ciliated columnar epithelium) and a histological surprise – a focus of carcinoid tumor without atypia [Figure 1d and e]. At 42-month follow-up, he is asymptomatic; the physical examination and imaging findings are normal.

Teratomas are uncommon pediatric germ cell tumors, with 3.5%–4% being retroperitoneal. Malignant transformation in a mature teratoma occurs in 1%–3% of cases, commonly into a squamous cell carcinoma (75%–87%). A carcinoid tumor is documented in only 6% of cases.[123] Primary carcinoid tumors are low-grade malignancies with neuroendocrine differentiation, commonly encountered in the gastrointestinal tract (85%) or bronchopulmonary tree (10%). In adults, most carcinoid tumors arise in gonadal teratomas from such cells. Only 10% secrete vasoactive peptides to manifest the carcinoid syndrome and increased urinary 5-hydroxyindoleacetic acid.[4] Isolated reports document their occurrence elsewhere – thymus, spinal cord, kidney, retroperitoneum, adrenal, and pelvis.[5] Their clinical behavior and prognosis is unclear, and it is recommended to evaluate for metastases and a cryptic primary site.[4]

In the present case, the carcinoid focus was incidentally detected during extensive histopathological evaluation. No sites of primary tumor or metastasis were evident. This is the youngest reported case with a retroperitoneal teratoma harboring a primary carcinoid tumor reported till date. Complete surgical excision and meticulous sampling from the solid parts of a teratoma characterizes rare tumoral components that impact on the prognosis. The lack of hemodynamic effects after accidental division of the IVC implies adequate retroperitoneal collateralization with the chronic occlusion.

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