V600E mutation in the wrong place: a case of concomitant polycythemia vera, hairy cell leukemia, and thyroid adenoma.

BACKGROUND

Polycythemia vera (PV) is one of the Philadelphia-negative myeloproliferative neoplasms (MPN), characterized by a pan-myelosis with an erythroid-predominant proliferation mainly driven by somatic V617F gain-of-function mutation. Hairy cell leukemia (HCL) is a rare B-cell lineage lymphoproliferative disease (LPD) with a typic immunophenotypic profile. V600E, leading to constitutive activation of the RAF/MEK/ERK signalling pathway and increased cell proliferation, is identified as the driver mutation in almost all cases. Although the risk of developing an LPD is significantly increased in patients with MPN compared with the general population, few cases of co-occurring PV and HCL are reported to date. is one of the most frequently mutated oncogenes in human cancer and some point mutations were identified in multiple neoplasms in addition to HCL, including follicular and papillary thyroid adenoma and carcinoma.

CASE PRESENTATION

Here we report a molecular diagnostic challenge in a woman with a concomitant diagnosis of V617F PV, V600E HCL, and Q61K thyroid follicular adenoma.

CONCLUSION

In the age of molecular and precision medicine, this case underlines the importance of integrating molecular results with clinical, radiologic, cytologic, and histopathologic investigations.