Diagnosis and Treatment > Signs and Symptoms
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Medical Genetics, Shizuoka General Hospital, Shizuoka, Japan
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Summary
Pheochromocytomas (PCCs) and paragangliomas (PGLs) are rare tumours with a heterogeneous genetic background. Up to 40% of apparently sporadic PCC/PGL cases carry 1 of the 12 gene germline mutations conferring genetic susceptibility to PCC/PGL. Although the precise mechanisms are unclear, TMEM127 is one of the rare responsible genes for PCC/PGL. Here we report the case of a patient with familial PCC having a novel TMEM127 variant (c.119C > T, p.S40F). In silico prediction analysis to evaluate the functional significance of this variant suggested that it is a disease-causing variant. A PCC on the left side was considered to be the dominant lesion, and unilateral adrenalectomy was performed. The histopathologic findings were consistent with benign PCC. A loss of heterogeneity of the TMEM127 variant was detected in the surgically removed tumour.
Learning points:
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c.119C > T (p.S40F) is a novel TMEM127 variant that can cause pheochromocytoma.
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The tumour showed loss of heterozygosity of this TMEM127 variant.
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The clinical phenotype of this mutation is putative bilateral pheochromocytoma in the 4th decade.
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Unilateral adrenalectomy may be performed as the initial surgery in such cases.
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Search for other papers by Elham Reda in
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Summary
We present two cases of adrenal phaeochromocytoma in patients with a previous diagnosis of neurofibromatosis type 1 (NF1). One had an adrenergic phenotype. The other had a more noradrenergic phenotype. Both had large primary tumours, which increases the likelihood of malignancy. Both also had elevated plasma-free methoxytyramine, which has been linked with malignancy even in non-SDHB phaeochromocytomas.
Learning points
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Phaeochromocytoma can have varied clinical presentations.
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Methoxytyramine can be useful in the biochemical work-up of both SDHB-positive and SDHB-negative phaeochromocytoma.
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The utility of methoxytyramine as a marker of malignancy in NF1-related phaeochromocytoma is unclear, and cases with elevated titres warrant longer follow-up.
