Pheochromocytoma-Histopathological and Clinical Update

Background: The pheochromocytoma or paraganglioma PPGL is a metabolically active tumor originating from the chromaffin cells of adrenal medulla (pheochromocytomas) or from sympathetic or parasympathetic autonomic ganglia (paragangliomas). The exact incidence of pheochromocytoma is unknown, but it is estimated to occur in 2–8 cases per million people per year. It has been termed the great masquerader since clinical characteristics may mimic large variety of disease & result in erroneous diagnosis The estimated prevalence of pheochromocytoma in hypertensive adults is thought to range from 0.1 to 0.6%. The foremost investigation in cases where pheochromocytoma is suspected is usually increased urinary and plasma levels of catecholamines and their metabolites (metanephrines, normetanephrines & VMA). Radiological investigations are performed to localize the tumor in cases where blood works confirm the presence of this tumor. Histopathological and immunohistochemical features are accustomed to authenticate the diagnosis. Aim: In this study, the most frequently diagnosed tumor of adrenal gland-Pheochromocytoma along with their detailed histopathological, biochemical and clinical characteristics were studied in detail. Material and Method: A retrospective 5 year study was carried out from 2015 to 2019 of pheochromocytomas. Brief clinical history was taken along with other relevant biochemical investigations, hormonal assays and radiological findings. Histopathological data was collected and relevant details were noted from the records maintained in the department of pathology at SKIMS Srinagar. Routine Hematoxylin and Eosin stain andchromaffin reactions were employed. Immunohistochemistry was done wherever required. The clinical and findings of H&E sections, special stains and immunohistochemistry were compiled to arrive at a final diagnosis. The results of the study were compared with the literature. Results: Out of 70 cases of adrenal masses, pheochromocytoma (31 cases) was the most common tumor observed. The most common symptom was hypertension, followed by sweating attacks along with palpitations.CT scan done on 28 cases revealed heterogenous mass which showed greater enhancement on contrast phase.The 24-hr urinary levels of VMA was elevated in 16 (51.6%) cases of pheochromocytoma and the values were ranging in between 44.5mg-76mg/24h.Grossly, cut-section was dark brown due to chromaffin reaction.7 cases were showing cystic degeneration and confluent necrosis was present in 14 cases and 3 cases showed vascular invasion histologically. Pass score was ≥4 in 9cases and <4 in remaining 22 cases. Immunohistochemistry panel used included chromogranin, synaptophysin, S100, Melan-A, Inhibin, PanCK (AE1, AE30) out of which positivity for Chromogranin, S-100, synaptophysin was noted. Conclusion: We conclude that the following clinicopathological parameters should be taken into account for proper diagnosis and risk assessment of malignant behavior of pheochromocytoma.proper clinical evaluation biochemical markers, location, size, PASS score, Immunohistochemical markers. Application of these criteria to a large cohort of cases will help in clinical practice.