Retroperitoneal oncocytoma: case report and review of the imaging features

Prognosis of Adrenal Oncocytic Neoplasms (AONs): Literature Review of 287 Cases and Presentation of the Oldest Patient

INTRODUCTION

The adrenocortical oncocytic neoplasms (AONs) are rare tumors of the adrenal gland, classified as oncocytoma (AO), oncocytic neoplasm of uncertain malignant potential (AONUMP) and oncocytic carcinoma (AOC). The aim of this study was to perform a review of the literature, in order to evaluate the prognosis of these rare cancers. We also reported the oldest patient with AON.

METHODS

A comprehensive literature review using as key words "adrenal oncocytoma", "adrenal oncocytic neoplasm", and "adrenal oncocytic carcinoma" was performed.

REPORT OF THE CASE

We report the case of an 88-year-old woman receiving a left open adrenalectomy for an AON (15 × 10 × 8 cm). The considerable size and weight together with the presence of necrosis were indicative for a lesion with an uncertain potential for malignancy, according to Weiss modified criteria. After two years, the patient was free from any sign of recurrence.

RESULTS

Only 287 AONs were detected in the scientific literature, exploring OVID, MEDLINE, PubMed and SCOPUS as dataset. These tumors are usually incidentalomas with an unpredictable malignant potential. Surgical resection remains the mainstay of treatment for AON.

CONCLUSION

AO and AONUMP have an excellent prognosis and a low mortality rate, with only three cases of recurrence reported in the literature and one metastatic case four years after first adrenal surgery. In contrast, AOC carries a high risk of local relapses, distant metastasis, and a significantly higher mortality rate (30%). Surgical resection remains the primary treatment for adrenal oncocytic neoplasms.

Adrenocortical oncocytic neoplasm: A systematic review

BACKGROUND

Adrenocortical oncocytic neoplasms are rare tumors, generally regarded as benign and hormonally nonfunctional. We performed a systematic review to update the literature on adrenocortical oncocytic neoplasms by reviewing patient and tumor characteristics, as well as management trends, because the literature is composed of predominately single-case reports.

METHODS

A systematic search was performed in PubMed, Embase, and Cochrane Library through June 2017. Malignant potential was determined by applying the Lin-Weiss-Bisceglia criteria to cases.

RESULTS

Included for analysis were 84 citations describing 140 adrenocortical oncocytic neoplasms, including our own case. These were diagnosed predominantly in females (66%), on the left side (64%), and were nonfunctional (66%). Average age at diagnosis was 44 years (2.5-77), and median tumor size was 80 mm (16-285). A total of 35% of adrenocortical oncocytic neoplasms were benign, 41% borderline, and 24% malignant. Male patients were more likely to have a malignant tumor compared with females (36% versus 18%, P = .035). The 5-year overall survival for benign adrenocortical oncocytic neoplasms was 100%, borderline 88%, and malignant 47%. Hormonal function did not discriminate malignant from benign lesions. Adrenocortical oncocytic neoplasms that stained positive for synaptophysin (50%, P < .001) and negative for vimentin (62%, P = .009) are more often benign.

CONCLUSION

We found that the majority of adrenocortical oncocytic neoplasms (65%) were either malignant or had malignant potential, contrary to the previous literature. The Lin-Weiss-Bisceglia criteria are useful in identifying those patients for whom closer surveillance is warranted, because their prognosis is dependent on the Lin-Weiss-Bisceglia diagnosis.

Oncocytic adrenocortical neoplasm arising from adrenal rest in the broad ligament of the uterus

Oncocytic adrenocortical neoplasm is characterized by abundant eosinophilic cytoplasm containing mitochondria, occasional nuclear atypia and diffuse growth pattern. Oncocytic adrenocortical neoplasm arising in adrenal rest is, however, extremely rare. We report a case of oncocytic adrenocortical neoplasm arising in adrenal rest of the broad ligament with associated marked lipomatous metaplasia. A well circumscribed tumor was accidentally detected in the pelvic cavity of a 29 year old Japanese woman, adjacent to the broad ligament of the uterus. The tumor was composed of large eosinophilic cells associated with diffuse growth pattern and abundant mature adipose tissue admixed with foci of clear cells. Both steroidgenic factor 1 (SF-1) and alpha-inhibin were immunohistochemically positive in tumor cells. Abundant mitochondria detected by immunohistochemical and electron microscopic examination confirmed the diagnosis of oncocytic adrenocortical neoplasm. The absence of necrosis, capsular and vascular invasion as well as the low mitotic index indicated the benign potential of this tumor. The tumor cells were also positive for dehydroepiandrosteron-sulfotransferase (DHEA-ST), 17β-hydroxysteroid dehydrogenase type 5 (17β-HSD5), 3β-hydroxysteroid dehydrogenase (3β-HSD) and steroid 17α-hydroxylase (P450-c17), suggesting a possible production of testosterone of this tumor. This is the first reported case of oncocytic adrenocortical adenoma arising in adrenal rest of the broad ligament.

Thoracoscopic surgery for pulmonary oncocytoma, an uncommon neoplasm

Oncocytoma is an uncommon neoplasm with a characteristic histologic feature of abundant eosinophilic granular cytoplasm. It almost always occurs in kidney, thyroid, or salivary gland. Pulmonary oncocytoma is a rare pulmonary neoplasm, with fewer than 10 cases reported so far in the available English literature. We encountered one such case that was successfully managed by thoracoscopic lobectomy.