Penetrating wounds of the hand with an embedded foreign body are common in active children and manual workers. Organic material, particularly thorns, can cause an inflammatory tissue reaction, ranging from a localized foreign body granuloma to a severe soft tissue and osseous reaction.
We report the case of a 57-year-old man presented to our emergency department with a painful swelling of his fourth right finger. He had fallen into bushes 4 month prior to his presentation. Plain radiographs showed a solid periosteal new-bone formation along the second phalanx, interrupted by a rounded well-limited radiolucent area at the mid-phalangeal level that we described like a “crab claw periosteal reaction”.
The osteoblastic reaction to an organic foreign body is very rare, we report an exceptional case of an unusual osteoblastic reaction to a retained organic foreign body in the hand that has been to our knowledge only once reported in the literature.