Primary adrenal teratoma: An unusual tumor - Challenges in diagnosis and surgical management.

We report a rare case of a 25-year-old lady who presented with right hypochondriac pain associated with weakness for 3 months. Her hormonal evaluation was normal. Computed tomography scan revealed an adrenal mass for which a right open transperitoneal adrenalectomy was performed, and the lesion was diagnosed as mature teratoma on histopathological examination. Teratoma is an unusual neoplasm which arises from one or all the three germ layers. Extragonadal teratomas are rare in adults as compared to children and are mostly retroperitoneal in location, constituting only 4% of all primary teratomas. Primary adrenal teratomas are even rarer and to the best of our knowledge, only eight cases have been reported in adults in the past 10 years. Adrenal teratoma can pose a diagnostic challenge because radiologically it mimics myelolipoma, angiomyolipoma, liposarcoma, or pheochromocytoma. Mature teratomas are usually benign but may possess malignant potential, the chances of which are greater in adults as compared to children, making it an important entity requiring a proper diagnosis and management.

Introduction

Teratomas are unusual tumors that are derived from totipotent cells with their origin from more than one or usually all three germ cells, i.e., ectoderm, mesoderm, and endoderm. Teratoma is a rare neoplasm with an incidence of 0.9/100,000 population.[1] Most common sites are gonads, sacrococcygeal, mediastinal, and pineal region.[2] Teratomas that occur in infancy and early childhood are usually extragonadal, whereas those found in adults are more commonly located in the gonads.[34] It represents an infrequent entity when found as primary retroperitoneal neoplasm in adults. Among the retroperitoneal teratomas, primary adrenal teratomas are extremely rare. We report one such case of mature teratoma in right adrenal gland in an adult female.

Case Report

A 25-year-old lady presented with a history of right side upper abdominal pain for 3 months, which was accompanied with progressive weight loss ~ approximately 10 kg during this period. There was no history suggestive of any adrenal dysfunction or family history related to familial syndromes. On physical examination, she was normotensive and functional workup for adrenal gland was also within normal limits. Contrast-enhanced computed tomography (CT) scan of abdomen revealed a large heterogeneous mass in right adrenal measuring 20 cm × 15 cm with few cystic areas, fat content, and calcifications [Figure 1a]. Hence, a differential diagnosis of adrenal myelolipoma (in view of fat contents) and malignancy (in view of large heterogeneous mass) was considered. Surgical resection was planned. Intraoperatively, the tumor was extending in the retrocaval area just below the liver and was difficult to mobilize. Right adrenalectomy was performed successfully [Figure 1b]. The postoperative period was uneventful, and she was discharged on 6th postoperative day.

Figure 1

(a) Computed tomography scan of abdomen showing a large heterogeneous mass (white arrow) in right adrenal measuring 20 cm × 15 cm with few cystic areas, fat content, and calcifications. (b) Adrenelectomy specimen (c) Cut surface displaying (white arrow) a variegated appearance with prominent fatty area

The specimen was sent for histopathological examination. On gross examination, the specimen measured ~ 19 cm × 15 cm. The outer surface was bosselated and congested. The cut surface showed a mass with a variegated appearance. The mass was solid and cystic in nature with predominance of adipose tissue [Figure 1c]. Further, sectioning was difficult due to areas of marked calcification. Normal adrenal was not identified grossly.

On microscopic examination, a tumor was identified which was composed of ectodermal, endodermal, and mesenchymal elements characterized by presence of multiple cysts lined with squamous cells, and ciliated columnar epithelial cells, glands, cartilage, bone, bone marrow, muscles as well as large areas of glial tissue. Some normal adrenal gland tissue was also observed at the periphery in the form of nodule composed of cells with clear cytoplasm. No immature component was seen. Hence, the final diagnosis was given as primary mature adrenal teratoma [Figure 2].

Figure 2

Microscopic examination of adrenelectomy specimen displaying: (a) startified squamous epithelium, (b) respiratory epithelium, (c) cartilage, (d) hematopoietic component, (e) glial tissue, (f) adrenal tissue [(a), (b), (c) – 400X and (d), (e), (f) – 200X; H&E stain]

Discussion

Teratoma is neoplasms comprising tissues derived from more than one germ layer. In adults teratomas predominantly arise in gonads. Primary extragonal teratoma in retroperitoneal locations are very rare and constitute only 4% of primary teratomas.[123] In Adrenal gland, teratoma is so rare that when searched in PubMed only total of 14 cases were retrieved in the past 10 years, with only 8 adult cases reported.[5] We report a case of a primary mature teratoma in the right adrenal gland in an adult female.

Most patients present with an incidentally detected nonfunctional solitary adrenal mass. Sometimes there may be vague symptoms such as abdominal distension, dull flank/epigastric pain, or it may also present as intestinal obstruction caused by compression.[6] Radiographic investigations play an important role in diagnosing teratomas. CT/magnetic resonance imaging scans can better distinguish between fat (adipose tissue) and bone (calcified) masses.[789] Due to fat contents and heterogeneous density mass differential diagnosis of adrenal myelolipoma, angiomyolipoma, liposarcoma, pheochromocytoma, or malignancy is usually considered. In the present case on gross examination, a major fat component was identified which was forming a nodule at one pole. Other differential diagnosis of retroperitoneal teratomas includes ovarian tumors, renal cysts, adrenal tumors, Wilm's tumor, sarcomas, retroperitoneal fibromas, cystic neuroblastoma, congenital mesoblasticnephroma, hemangiomas, xanthogranuloma, enlarged lymph nodes, and perirenal masses.[6]

The majority of mature teratomas in the retroperitoneum are benign neoplasms, and 26% are malignant. The diagnostic criteria in the present case are completely in accordance with the benign mature teratoma. In the case of a retroperitoneal tumor, germ cell tumors should be considered and tumor markers examined before surgery.[10] The malignancy rate of 25.8% in adults is significantly higher than 6.8% rate documented in children.[1112] Surgical excision is the method of choice for the diagnosis as well as treatment of the mature teratoma.[11] We did open transperitoneal adrenalectomy in view of large size (20 cm) and suspicion of malignancy. Teratomas are relatively resistant to chemotherapy and radiotherapy. Prognosis is usually excellent after complete resection but because of the risk of malignant transformation a close follow-up is recommended.

Hence, to conclude primary adrenal teratomas are very rare and should be considered in the differential diagnosis of retroperitoneal mass. The prognosis is excellent after complete resection; however, an adequate follow-up is advisved in view of risk of malignant transformation.

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