Myofibroblastic proliferation of the tongue with significant differential diagnosis - a case report and review of literature

Lesions of Myofibroblastic origin are very rare to occur in the tongue, sometimes they have an aggressive presentation that could be easily misdiagnosed as malignancy. There is not a clear etiology, however trauma and infection are suggested factors. Histologically, myofibroblastic and inflammatory cells are present.

Here we present a case report of a 46-year-old Caucasian female that presented with approximately three year-history of laceration of dorsum tongue that was recently further traumatized by biting it. The clinical exam revealed a traumatic raised nodular lesion on the right side towards the mid-line of dorsum tongue.

The histological findings revealed a poorly demarcated mass of atypical proliferating spindle cells, infiltrating into the muscle fibers and extending to the base of the specimen. Desmin and Myogenin, were focally positive in regenerating/degenerating muscle cells. MSA was diffusely positive in the spindle cells. Within the submucosa there was a proliferation of actin positive myofibroblasts with associated inflamed granulation tissue containing scattered acute and chronic inflammatory cells. CK (AE1/AE3), CD31, S-100, and HMB45 were negative for the spindle cells. CD31 highlighted the small blood vessels in the granulation tissue. Perivascular necrosis was noted. Ki-67 showed high proliferative index (>25%). Factor XIIIa highlighted fibroblasts and MyoD1 showed scattered positivity.

The final diagnosis was in favor of a benign reactive myofibroblastic proliferation.

Myofibroblastic proliferation lesion is a challenging diagnosis because of the clinical appearance and the histological features mimicking malignancy. For this reason, it is imperative to have an accurate diagnosis to prevent unnecessary radical treatment.