Anteroposterior x-ray of a woman’s hand showing a centrally located radiolucent lesion at the base of the middle phalanx of the small finger
Lateral x-ray of the patient’s hand
A 38-year-old woman presents with a bump on her right small finger that she noticed a few months ago. She has no significant pain around the bump but does occasionally have sensitivity in the area. Upon examination, she has full range of motion of the small finger. She has tenderness to palpation over the ulnar border of the middle phalanx. Anteroposterior and lateral x-rays of the finger show a centrally located radiolucent lesion at the base of the middle phalanx of the small finger. Magnetic resonance imaging (MRI) shows medullary expansion and corticol thinning but no corticol breakthrough or soft tissue involvement.
This case has been brought to you in partnership with the Journal of Orthopedics for Physician Assistants.
Submit your diagnosis to see full explanation.
The most common primary bone tumor in the hand is an enchondroma, which is the most likely diagnosis for this patient. An enchondroma is a benign, cartilage-forming tumor that most often occurs in adolescents and young adults. An enchondroma is often described as an island of cartilage within bone that never transforms to normal bone. The most common location where these occur in the hand is the proximal phalanx, followed by the middle phalanx, and then the metacarpals. Phalangeal fractures can be symptomatic, as cortical thinning can result in a stress reaction or fracture.co
The patient’s history of slow growth and little pain indicate that the bone lesion is benign. Malignant lesions typically have rapid growth, increasing pain, and night pain. The absence of cortical destruction and soft tissue involvement noted on the patient’s magnetic resonance imaging (MRI) also help rule out a malignant chondrosarcoma from the diagnosis.
Most enchondromas that are not at a high risk for fracture can be treated with observation. Observation includes follow-up x-rays every 3 to 6 months for a year and then annually to ensure the lesion is not changing in size. Treatment of large lesions that are likely to fracture includes curettage to remove all of the tumor and then packing the void with bone graft. This is a relatively common procedure that does not require referral to an orthopedic oncology specialist. Bone graft can include autogenous bone, bone graft substitute, and allograft. Generally, the resected tumor is sent to pathology to confirm the diagnosis after surgery. If a fracture occurs through the thinned cortical rim, the fracture should be allowed to heal before curettage and bone grafting are performed. Recurrence after surgery is rare, as is malignant transformation of the lesion to a chondrosarcoma.
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).
Editor’s Note: This article was updated on July 27, 2016.
- Plate AM, Lee SJ, Steiner G, Posner MA. Tumor-like lesions and benign tumors of the hand and wrist. J Am Acad Orthop Sur. 2003;11(2):129-141.
- Woon C. Enchondromas. Orthobullets web site. http://www.orthobullets.com/pathology/8018/enchondromas. Updated June 17, 2015. Accessed July 25, 2016.