Nodular fasciitis is a benign, reactive myofibroblastic tumor that is often mistaken for a sarcoma because of its histological appearance and rapid growth. Involvement of a finger is extremely rare. We report a case of nodular fasciitis of the thumb, accompanied by bone erosion. Magnetic resonance findings suggested the possibility of a malignancy, which could have led to misdiagnosis as a malignant soft tissue sarcoma. Instead, the lesion was treated by excisional biopsy, which confirmed nodular fasciitis. There has been no evidence of local recurrence at recent follow-up, 1 year after surgery. This case illustrates that, to avoid unnecessarily aggressive surgery, nodular fasciitis must be included in the differential diagnosis for any finger lesion that resembles a sarcoma, even if bone erosion is present.
Adult ; Biopsy ; Diagnosis, Differential ; Fasciitis/*diagnosis/surgery ; Female ; Finger Phalanges/pathology/*radiography ; Humans ; Magnetic Resonance Imaging ; Sarcoma/*diagnosis ; Soft Tissue Neoplasms/*diagnosis ; Thumb/*pathology/surgery

Nodular fasciitis is a benign, reactive myofibroblastic tumor that is often mistaken for a sarcoma because of its histological appearance and rapid growth. Involvement of a finger is extremely rare. We report a case of nodular fasciitis of the thumb, accompanied by bone erosion. Magnetic resonance findings suggested the possibility of a malignancy, which could have led to misdiagnosis as a malignant soft tissue sarcoma. Instead, the lesion was treated by excisional biopsy, which confirmed nodular fasciitis. There has been no evidence of local recurrence at recent follow-up, 1 year after surgery. This case illustrates that, to avoid unnecessarily aggressive surgery, nodular fasciitis must be included in the differential diagnosis for any finger lesion that resembles a sarcoma, even if bone erosion is present.
Adult ; Biopsy ; Diagnosis, Differential ; Fasciitis/*diagnosis/surgery ; Female ; Finger Phalanges/pathology/*radiography ; Humans ; Magnetic Resonance Imaging ; Sarcoma/*diagnosis ; Soft Tissue Neoplasms/*diagnosis ; Thumb/*pathology/surgery