The patient was referred to left adrenalectomy.
Macroscopy: Labelled "Left adrenal gland." An adrenal gland with an ovoid adrenal tumour, 78 g, with uninvolved adrenal gland measuring 14 x 18 x 6 mm with up to 10 mm of attached fat, and ovoid tumour 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 haemorrhage 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 tumour comprises epithelioid cells arranged in nests and trabeculae with an associated hyalinised fine calibre 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 tumour necrosis. There is no expanded large and confluent tumour nests or diffuse growth. Tumour cellularity is not increased and there is no cell spindling. Ganglion cells are not identified. Foci of cystic degeneration, hyalinisation, haemorrhage and haemosiderin deposition are seen.
The tumour is confined to the fibrous capsule with no evidence of extracapsular or extra-adrenal extension and the tumour is clear of excision margins.
The adjacent adrenal gland is unremarkable.
Using immunohistochemical stains, the tumour cells show diffuse positive immunoreactivity for chromogranin and synaptophysin and are negative for melanA, pancytokeratin and calretinin. An S100 stain highlights sustentacular cells around tumour cell nests. There is also weak staining of tumour cells. Ki67 index is <5%.
The features are those of a phaeochromocytoma. The phaeochromocytoma of the adrenal gland scaled score (PASS) is 2 (necrosis present) which favours a benign behaviour (Am J Surg Pathol 26(5):551-566, 2002).
Conclusion: Left adrenalectomy: Phaeochromocytoma (pT2).