A 60 years old female presented with a 1cm right arm mass.

    Clinical History:

    The patient is a 60 year old female that presented to an outside community clinic with complaints of a right arm mass. No significant past medical history was provided to us and the treating surgeon considered a cyst.

    Microscopic Description:

    Excision of the right arm mass grossly measured  1 cm and showed a poorly circumscribed tumor centered in the deep dermis arranged in cords and sheets that infiltrated into the fibrous septa of the subcutis. The tumor cells were large and had abundant eosinophilic granular cytoplasm, indistinct cell borders, and had predominately small uniform bland nuclei. The tumor cells had an overall benign appearance, but demonstrated focal pleomorphism along with scattered frequent mitosis. Atypical mitosis or tumor necrosis is not identified. S100 positivity supports a diagnosis of granular cell tumor combing with histological findings. A Ki67 immunostain highlighted an increased cell proliferation rate (5-10% with area variation). PHH3 immunostain highlighted frequent mitotic figures that corresponded to a count of 9/10 HPF.

    Diagnosis:

    GRANULAR CELL TUMOR WITH A HIGH CELL PROLIFERATION RATE (5-10%) AND FREQUENT MITOSIS (9/10HPF) INVOLVING THE DEEP DERMIS AND SUBCUTIS, CAN BE CLASSIFIED AS AN ATYPICAL VARIANT.

    Conference: