Presentation
Left flank pain.
Patient Data
There is a large heterogeneous mass lies within the left adrenal bed that has heterogeneous and mostly peripheral enhancement on portal venous phase (up to 170 HU). A large portion of the central lesion does not visibly enhance. The spontaneous Hounsfield unit reading measures approximately 20, inconsistent with macroscopic fat. There is retained enhancement on the delayed phase.
The lesion is inseparable from the left adrenal gland. It does not obviously arise from the adjacent left kidney, which itself enhances normally.
There is a 9 mm enhancing nodule medial limb right adrenal gland. Too small to obtain an accurate Hounsfield unit reading on the precontrast study.
The right kidney is normal.
No retroperitoneal lymphadenopathy.
Conclusion: Left retroperitoneal mass is likely of adrenal origin. The differential diagnosis includes pheochromocytoma and adrenal carcinoma, however, the bilateral nature of the process makes the later less likely.
The patient was referred to left adrenalectomy.
Macroscopy: Labeled "Left adrenal gland." An adrenal gland with an ovoid adrenal tumor, 78 g, with uninvolved adrenal gland measuring 14 x 18 x 6 mm with up to 10 mm of attached fat, and ovoid tumor arising in the adrenal medulla, measuring 58 x 47 x 45 mm. The lesion is focally surrounded by overlying adrenal cortex and fat and has a smooth grey intact capsule. Cut surface shows yellow and focally white tissue with focal hemorrhage and no necrosis. There is no evidence of perforation through the capsule. No lymph nodes identified. The adjacent adrenal is unremarkable.
Microscopy: The sections show adrenal gland with a well-circumscribed, encapsulated neoplasm arising from the medulla. The tumor comprises epithelioid cells arranged in nests and trabeculae with an associated hyalinised fine caliber capillary network. The cells have eccentric round to ovoid moderately pleomorphic nuclei, vesicular chromatin, small nucleoli and abundant, finely granular amphophilic cytoplasm. The nuclear to cytoplasmic ratio is not increased and macronuclei and nuclear hyperchromasia are not identified. There are occasional cells with intracytoplasmic hyaline globules and scattered mitotic figures (formal mitotic count 1/10HPF) but no atypical mitotic figures are seen. No angiolymphatic invasion is seen. There are foci of central tumor necrosis. There is no expanded large and confluent tumor nests or diffuse growth. Tumor cellularity is not increased and there is no cell spindling. Ganglion cells are not identified. Foci of cystic degeneration, hyalinisation, hemorrhage and hemosiderin deposition are seen.
The tumor is confined to the fibrous capsule with no evidence of extracapsular or extra-adrenal extension and the tumor is clear of excision margins.
The adjacent adrenal gland is unremarkable.
Using immunohistochemical stains, the tumor cells show diffuse positive immunoreactivity for chromogranin and synaptophysin and are negative for melanA, pancytokeratin and calretinin. An S100 stain highlights sustentacular cells around tumor cell nests. There is also weak staining of tumor cells. Ki67 index is <5%.
The features are those of a pheochromocytoma. The pheochromocytoma of the adrenal gland scaled score (PASS) is 2 (necrosis present) which favors a benign behavior (Am J Surg Pathol 26(5):551-566, 2002).
Conclusion: Left adrenalectomy: Pheochromocytoma (pT2).
Surgical sutures in the left suprarenal region and in the left renal pelvis. Left double J stent noted in situ.
There is a hyperdense lesion seen in the uncinate process of the pancreas measuring 0.5cm x 0.7cm. No washout in the delayed phase of the study. No dilatation of the pancreatic duct or CBD. Clear margin between this lesion and the SMV. The lesion is not continuous with any blood vessel.
The previously seen right adrenal lesion has marginally increased.
There is a collection seen in the splenorenal fossa and in the posterior perinephric space measuring.
No bowel-related mass or bowel wall thickening.
No significant abdominal or pelvic lymph nodes.
Genetic testing was performed: " VHL gene PCR and sequence analysis shows heterozygosity for c.445G> A (p.Ala149Thr) germline mutation in Exon 2 of VHL gene. This is a pathogenic mutation in the HGM database. Consistent with von Hippel Lindau disease".
Case Discussion
This case illustrates bilateral pheochromocytomas (left confirmed on histology) and a small presumed pancreatic neuroendocrine tumor in the setting of Von Hippel-Lindau disease.
The presentation scan shows bilateral hypervascular adrenal lesions, which at this age group, almost invariably represents phaeocromocytomas (c.f. adrenal carcinoma will nor present bilaterally and metastases are very uncommon at this epidemiology). The 10% rule of thumb for phaeocromocytomas remind us that they can be bilateral, but also that they can bd a manifestation of an underlying genetic condition.