Presentation
Right hand swelling for one year, which is increasing in size.
Patient Data
A well circumscribed lobulated subcutaneous lesion at the volar surface of the right fourth webspace (between the fourth and fifth metacarpophalangeal joints), insinuating in between the fourth and fifth flexor digitorum profundus tendons.
It demonstrates isointense to intermediate signals on T1WI, heterogeneously hyperintense signals on T2WI, and STIR with no suppression on fat saturated sequences. Post Gadolinium, it shows mild heterogenous enhancement.
A few small ring-like structures with peripheral hyperintensity on T2WI and STIR, represent the fascicular sign.
Clear fat plane is seen between this lesion and the adjacent 4th/5th flexor digitorum tendons, which have normal hypointense signal on all sequences.
No abnormal signal intensity within the adjacent interosseous muscles.
Normal marrow signals of the fourth and fifth proximal phalanges are preserved without cortical erosion.
Case Discussion
Overall MR features are suggestive of peripheral nerve sheath tumour, including schwannoma or neurofibroma. Surgical excision and histopathological examination correlation are advisable.
Histopathology examination of the right hand swelling lesion:
MICROSCOPY:
Sections show a well circumscribed lesion composed of neoplastic cells which are spindle in shape and arranged in multiple short fascicles. There are densely cellular areas with nuclear palisading forming Verocay bodies (Antoni A), alternating with paucicellular areas (Antoni B). Intervening stroma appears hyalinized. There is no cytologic atypia or evidence of malignancy identified.
INTERPRETATION:
Upper extremity, Right Hand Swelling: Schwannoma. No evidence of malignancy.
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