Nonsporadic cases and unusual morphological features in pheochromocytoma and paraganglioma.

ABSTRACT

BACKGROUND: Pheochromocytomas and paragangliomas are well-defined entities. Some of their nonsporadic associations and unusual morphological appearances are not universally appreciated. DESIGN: We reevaluated all adrenal pheochromocytomas and extra-adrenal paragangliomas seen at our institution in the period from 1980 through 1995 for their nonsporadic presentation or unusual morphological features and for the presence of sustentacular cells. RESULTS: Among 71 pheochromocytomas and paragangliomas in 60 patients, there were seven nonsporadic cases (11.5%), including three familial cases, two cases of multiple endocrine neoplasia 2a syndrome, one case associated with neurofibromatosis type 1, and one case of incomplete Carney's triad. In addition, we saw two cases of pheochromocytoma associated with metachronous malignant melanoma and one case of multicentric paraganglioma in a patient with Maffucci's syndrome. Unusual morphological features were as follows some degree of coexisting cortical hyperplasia (eight cases), vacuolar degeneration of tumor cells (three cases), composite pheochromocytoma (one case), presence of pheochromoblasts and calcospherites (one case), melanin pigmentation (two cases), and insular growth pattern (four cases); the latter was associated with malignant behavior in two cases. Sustentacular cells varied in number but were consistently numerous in all nonsporadic cases. CONCLUSIONS: Nonsporadic cases of pheochromocytoma comprise around 10% of all cases in this as in other series. Some other, less well-recognized associations, eg, with malignant melanoma, may also belong to this group. Unusual morphological features occur in a substantial number of cases and may cause diagnostic problems.