| Abstract|| |
Adrenal oncocytic tumors are rarely encountered. Most of the oncocytic tumors are benign and rarely malignant. Here we report a case of a 10-year-old male child presented with abdominal mass whose Contrast-Enhanced Computed Tomography (CECT) shows well-circumscribed tumor. Right adrenalectomy was carried out. Histopathologically, it was diagnosed as adrenal cortical oncocytic neoplasm of uncertain malignant potential (AONUMP). This case highlights that although adrenal oncoytic tumors are rare, we should consider this as a differential diagnosis while evaluating the patient for adrenal masses. The case is presented in view of its rarity, and distinguishing gross and microscopy appearance, the diagnosis of which was further confirmed with immunohistochemistry markers.
Keywords: Adrenal, cortical tumurs, immunohistochemistry, Oncocytic tumur
|How to cite this article:|
Ramamoorthi S, Jindal B, Deivasigamani A, Srinivas BH. Oncocytic adrenal cortical neoplasm of uncertain malignant potential – A rare case report. Indian J Pathol Microbiol 2022;65:692-4
|How to cite this URL:|
Ramamoorthi S, Jindal B, Deivasigamani A, Srinivas BH. Oncocytic adrenal cortical neoplasm of uncertain malignant potential – A rare case report. Indian J Pathol Microbiol [serial online] 2022 [cited 2022 Aug 15];65:692-4. Available from: https://www.ijpmonline.org/text.asp?2022/65/3/692/351618
| Introduction|| |
Oncocytic neoplasms are rare tumors, predominantly of benign nature. They can occur in thyroid, adrenal, kidney, salivary glands, parathyroid and pituitary glands, and rarely in the respiratory tract and choroid plexuses. Oncocytes are the epithelial cells which are acidophilic and packed with mitochondria.
Adrenal oncocytic tumors are an extremely rare type of adrenal cortical tumors. Only 150 cases have been reported in literature. We came across this tumour in a child who presented with abdominal mass.
| Case Report|| |
A 10-year-old male child presented with mass in right abdomen for 6 months. On physical examination, his pulse rate was 78 beats per minute, blood pressure was 90/70 mmHg, and on the abdomen, a 9 × 6 cm hard mass was felt in the right hypochondriac and lumbar region. It did not move with respiration, and was non-mobile. CECT of abdomen [Figure 1] showed a well-defined, mildly enhancing soft tissue density lesion with calcifications measuring 10.1 × 9.2 × 10.3 cm. It was noted in the subhepatic region abutting the segments 5 and 6 of liver. Inferiorly, the lesion was displacing the right kidney infero-medially and the right adrenal was not separately seen. His serum Vanillyl mandelic acid (VMA), Beta-HCG and AFP levels were within normal limits. Bone marrow biopsy was within normal limits. His serum cortisol, Free T3, T4, TSH, ACTH, FSH, LH was within normal limits. Only testosterone was minimally elevated at 846 ng/ml (normal range being 241–827 ng/ml). Right adrenalectomy was done. Intraoperatively, a well circumscribed tumor measuring 17 × 15 × 10 cm was noted in the right supra renal region replacing the right adrenal gland and was sent for histopathological examination. On gross examination, the outer surface of adrenal tumor in toto was 430 grams and well encapsulated [Figure 2]. On cutting surface, the tumour was homogenous, grey-brown with focal areas of hemorrhage and necrosis. It also showed areas of calcification.
|Figure 1: CECT abdomen showed well-defined, mildly enhancing soft tissue density lesion in right supra renal region|
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Microscopic examination revealed a tumor arranged in nests, sheets and focal alveolar pattern. These tumour cells had dense eosinophilic granular cytoplasm, with central round nuclei and inconspicuous nucleoli [Figure 3]a and [Figure 3]b. At places, these nuclei showed intranuclear inclusions and giant cell tumors were also seen [Figure 3]c and [Figure 3]d. Mitoses was 1/50 HPF. Focal coagulative tumor necrosis/dystrophic calcifications were noted. No vascular/capsular invasion was noted. On reticulin staining, it highlighted the intact reticulin network around the tumor cells. On immunohistochemistry, the tumour cells were strongly positive for adrenal cortical markers which included inhibin, patchy positivity for calretinin and cytokeratin [Figure 4]a and [Figure 4]b. It was negative for adrenal medullary markers including synaptophysin, chromogranin and S100. Ki67 labelling index was 1% [Figure 4 inset]. Also received ipsilateral, aorto-caval, mesenteric, contralateral and inter aortocaval nodes, all nodes were free of tumour. Morphological diagnosis of adrenal oncocytoma was made. On applying Lin–Weiss–Bisceglia (LWB) criteria (a diagnostic criteria for oncocytic adrenal cortical tumor) which includes major and minor criteria; as the specimen weighed 430 grams, the diagnosis of adrenal cortical tumor of uncertain malignant potential (AONUMP) was made.
|Figure 3: (a) Shows capsulated adrenal tumor with sheets and nests of tumor cells (H&E 4x); (b) Tumor cells with abundant dense eosinophilic cytoplasm (H&E 40X); (c) shows giant cell tumors, highlighted by arrow (H&E 40X); (d) shows intranuclear inclusion, highlighted by arrow (H&E 40X)|
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|Figure 4: (a) Tumor cells are strongly positive for inhibin (DAB 20X) (b) Patchy positive for calretinin (DAB 20X) Inset: Ki67: 1%|
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| Discussion|| |
Oncocytic variant of adrenocortical tumours are rare and constitute only around 10%. Most of the adrenal oncocytomas are benign, non-functional and incidentally diagnosed. But in our case, the patient presented with abdominal mass because of its large size. Adrenal oncocytic neoplasms usually present in age group ranging from 27–72 years with female predilection and most frequently encountered on the left side. However, the first description was confirmed by electron microscopy in 1986, and approximately 150 cases have been reported in the literature. The term “oncocyte” was first described in Greek, which indicated mass or bulk in 1950 by Hamperl. It usually describes a large, eosinophilic, granular cytoplasm characteristically seen in the thyroid gland, also described as Askanazy cell. The oncocyte is 1–2 times the size of normal acinar cells, contains characteristic eosinophilic granular abundant cytoplasm and is definitively confirmed by electron microscopy. It demonstrates the increased concentration of mitochondria in the cytoplasm of oncocytic cells. adrenal oncocytic tumors are rare subgroups of adrenocortical tumours. So far, only six cases of adrenal oncocytic neoplasm of uncertain malignant potential (AONUMP) have been described in literature. The adrenal cortical tumors are categorized histologically by Weiss criteria which includes 9 histologic features of oncocytic tumours to diagnose malignant tumours. The Weiss criteria includes high nuclear grade (based on Furhman criteria), mitotic rate >5/50 HPF, atypical mitotic figures, <25% clear cells, diffuse architecture, tumour necrosis, venous invasion, sinusoidal invasion and capsular invasion. Three out of nine criteria correlates with malignant behavior. Bisceglia et al. further modified the Weiss system based on major and minor pathological features displayed in the adrenal cortex for adrenal oncocytic tumors which came to be known as Lin–Weiss–Bisceglia (LWB) criteria. The major criteria include high mitotic activity >5/50HPF, atypical mitoses or venous invasion while minor criteria include large size >10 cm or weight >200 grams, necrosis, capsular or sinusoidal invasion. Tumors that display one major criterion are considered malignant and those that display one to four minor criteria are considered those of uncertain malignant potential. The tumours which are absent for both major or minor criteria are considered benign. In our case, the weight of the adrenal tumor was 430 grams; thus, one of the minor criteria was present. So, the final diagnosis of AONUMP was made. Postoperative follow-up of the patient after 6 months was unremarkable. The patient will be followed-up to check for any recurrence or metastases every six months for two years and then yearly for at least five years.
The therapeutic approach for these adrenal tumors depends on the size and function of the tumors. Surgical resection is the mainstay of treatment since adrenal oncocytic neoplasms (AON) usually presents as large masses. Nowadays laparoscopic/robot-assisted surgeries are performed as it has less morbidity and quick recovery of the patient. Since the mass is large in our case, it was removed by open laparotomy.
The prognosis of AON depends on the LWB criteria. Wong et al. studied and validated this method to differentiate AON and their behavior on metastasis and recurrence. Although the tumor has relatively benign behavior, there are studies which revealed recurrence in three cases out of 47 cases, over a follow-up period of 96 months. Another study by Son et al. reported a recurrence of AON after a follow-up period of 4 years.
| Conclusion|| |
Adrenal oncocytic neoplasms are usually large, benign, and non-functional. Radiological imaging including CT and MRI could be difficult to differentiate between benign and malignant, so microscopy can accurately help in the diagnosis, behavior and nature of the disease. Most of AONUMP are benign in nature and only a few cases have been reported in the literature. So the long-term progression of the disease was not clearly defined. Hence, clinical follow-up for a longer period is required.
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Written informed consent for publication of their clinical details/images was obtained from parent of the patient as the patient is under the age of 18 years.
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Conflicts of interest
There are no conflicts of interest.
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Bheemanathi Hanuman Srinivas
Department of Pathology, JIPMER, Puducherry - 605 009
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4]