Silent malignant intrathoracic pheochromocytoma

Silent pheochromocytoma and paraganglioma: Systematic review and proposed definitions for standardized terminology

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors with heterogeneous clinical presentations and potential lethal outcomes. The diagnosis is based on clinical suspicion, biochemical testing, imaging and histopathological confirmation. Increasingly widespread use of imaging studies and surveillance of patients at risk of PPGL due to a hereditary background or a previous tumor is leading to the diagnosis of these tumors at an early stage. This has resulted in an increasing use of the term "silent" PPGL. This term and other variants are now commonly found in the literature without any clear or unified definition. Among the various terms, "clinically silent" is often used to describe the lack of signs and symptoms associated with catecholamine excess. Confusion arises when these and other terms are used to define the tumors according to their ability to synthesize and/or release catecholamines in relation to biochemical test results. In such cases the term "silent" and other variants are often inappropriately and misleadingly used. In the present analysis we provide an overview of the literature and propose standardized terminology in an attempt at harmonization to facilitate scientific communication.

Pheochromocytoma of the posterior mediastinum undiagnosed until the onset of intraoperative hypertension

An asymptomatic 42-year-old man was diagnosed with a posterior mediastinal mass, most likely a nonfunctioning, benign, neurogenic tumor for which thoracoscopic surgery was initially indicated. However, the systemic blood pressure rapidly increased to a critical level immediately after starting the surgical manipulation of the tumor, which was suggestive of a hyperfunctioning pheochromocytoma. The tumor was removed after controlling the blood pressure and was histologically diagnosed as a pheochromocytoma. The patient had an uneventful course, and the tumor was proven to be sporadic through further postoperative investigations. The possibility of extraadrenal pheochromocytoma should be considered in the preoperative diagnosis of an intrathoracic paraaortic tumor, even in an asymptomatic patient.

Malignant nonfunctioning pheochromocytoma occurring in a mixed multiple endocrine neoplasia syndrome

OBJECTIVE

To present the first documented case of malignant nonfunctioning pheochromocytoma occurring in a mixed multiple endocrine neoplasia (MEN) syndrome.

METHODS

We describe the personal and family history of a 34-year-old man with headaches, increased serum prolactin levels, and hyperparathyroidism and review the details of his clinical course and treatment.

RESULTS

After diagnosis of a prolactinoma, bromocriptine therapy was implemented but eventually discontinued by the patient when severe headaches recurred. A transsphenoidal resection of a prolactinoma was performed; the patient continued to have abnormally high serum prolactin levels. Subsequent left lower flank pain prompted an exploratory laparotomy, and a left nephroad-renalectomy was performed. Pathologic examination disclosed a 1-cm tumor, consistent with malignant pheochromocytoma. Electron microscopy demonstrated neurosecretory granules. A hypercoagulable state complicated the course postoperatively. Despite chemotherapy, extensive metastatic disease ensued, and the patient died.

CONCLUSION

Although pheochromocytomas are usually associated with MEN type IIA and type IIB, this patient had a malignant pheochromocytoma, without the usual clinical and biochemical manifestations, in the setting of MEN type I.

Intrapericardial pheochromocytoma

A patient with intrapericardial pheochromocytoma is described, and the literature on this subject is reviewed. Iodine 131-labeled metaiodobenzylguanidine scintigraphy was superior to computed tomography in localizing the tumor. This newly introduced method is safe, specific, noninvasive, and may prove to be the method of choice for localizing pheochromocytomas. The patient was prepared for surgery with alpha- and beta-adrenoceptor blocking agents. The tumor was markedly adherent to the posterior wall of the left and right atria. Cardiopulmonary bypass was used to allow excision of the tumor. Hemostasis was attained with difficulty due to marked vascularity of the tumor.

Malignant phaeochromocytoma: report of a case and a critical review

A right adrenal phaeochromocytoma is described in a 64-year-old man. Metastases to bone and subsequent death following cord compression occurred within 2 years of diagnosis. Twenty-seven cases in the English literature have been reviewed since 1968. In three of these, the pathological proof was unsatisfactory for the diagnosis of malignancy, and one further case was inadequately documented. The variation in incidence of malignancy found in large retrospective series may relate to inconsistency in pathological criteria, as well as to selective reporting of cases.