Enchondroma is a usual bone tumor that appears in the metacarpals, carpals, and pharynx ^[1]. Less frequently, giant-cell tumors (GCT) ^[2] and aneurysmal bone cysts (ABCs) ^[3] were defined. It is quite uncommon to find other benign malignant tumors of the hand’s bones, including metastases ^[4]. With its lobules of hyaline cartilage and sporadic foci of calcification, it is thought to be the remains of a closed physis. They are therefore most frequently observed in the metaphyseal area of bones. About half of it affects the metacarpals and pharynx. Carpals are much less likely to be impacted. Men and women are equally present [5,6]. Most often found between the ages of ten and thirty, an enchondroma usually develops during skeletal growth and follows a pathologic fracture brought on by structural weakness. Excision along with reconstruction with autograft is more effective treatments for very large lesions with pathological fractures or recurrent lesions.

For 3 months, a 38-year-old female complained of pain as well as edema in her left hand. The patient has a history of a mishap that occurred 3 months ago. Radiographic evaluation was done by X-ray as shown in (Fig. 1a, b) and magnetic resonance imaging (MRI) as shown in (Fig. 2a, b and c) which revealed a well-marginated lytic lesion in the head, neck, and distal phalanx of the left 4^th finger and significant cortical destruction, completely replacing the bone in the affected region. Extensive adjacent soft tissue edema involving flexor and extensor tendons of the 4^th finger. There was no involvement of the metacarpophalangeal (MCP) joint.

Operative technique

The patient was laid in a supine position on a radiolucent table with the left arm on the side arm board under spinal anesthesia and axillary block with a tourniquet. The left upper and lower limb was cleansed with 10% betadine scrub and was draped in a sterile manner. A 5 cm incision was taken from the base of the left 2^nd metatarsal extending to the head as shown in (Fig. 3a). Superficial and deep dissection was done as shown in (Fig. 3b). 2^nd metatarsal was exposed and cut just distal from the base with the help of a saw as shown in (Fig. 3c). The metatarsal graft was harvested along with the volar plate, and medial and lateral ligament as shown in (Fig. 3d). Closure was done in layers and sterile dressing was done.

A 5 cm incision was taken over the left 4^th metacarpal from the base extending up to the 4^th MCP joint as shown in (Fig. 4a). Superficial and deep dissection was done as shown in (Fig. 4b, c and d). The lesion was excised from a shaft of the 4^th metacarpal 1 cm proximal to enchondroma with the help of C-arm as shown in (Fig. 5a). The metacarpal was removed as shown in (Fig. 5b) and the graft was inserted. 5-hole plate was fixed with appropriate size screws and a 1.2 mm K-wire had been passed from the head of a 5^th metacarpal toward the head of a 4^th metacarpal and another 1.2 mm K-wire had been passed from distal phalanx to head of 4^th metacarpal as shown in post-operative X-ray of (Fig. 6c and d). The capsule was repaired and closure was done in layers. Sterile dressing was done and below knee slab for the left lower limb and the ulnar gutter slab was given for the left upper limb.

Post-operative rehabilitation

Post-operatively below elbow slab was given for the patient to promote wound healing and fracture healing for 4 weeks. Regular antibiotics were given post-operatively.

After 2 weeks of surgery gradual wrist movements were started. Follow-up radiographs were taken every 4 weeks to check for union of bone. Upon radiographic union, finger movement was gradually started as tolerated by the patient. Radiographic healing was determined by bridging across three or four cortices on anteroposterior and lateral radiographs.

After 8 weeks of surgery, the radiograph showed a union of bone and K-wires were removed under local anesthesia and full finger movement was started. The patient achieved full finger movement in 12 weeks post-operatively. A radiograph at 12 weeks showed a union of bones as shown in (Fig. 7a and b). The patient resumed normal daily activities in 18 weeks and was able to perform painless full finger movement in 20 weeks as shown in Figs. 8, 9, and 10.

The most prevalent benign hand tumor is enchondroma. It is composed of hyaline cartilage lobules, which are thought to be the remains of a closed physis and occasionally have foci of calcifications ^[4]. Radiographs of hand enchondromas demonstrate a well-demarcated lucent lesion typically centrally located in the diaphysis of the involved tubular bone. The lesion may extend to the end of a small tubular bone. The contour of the lesion is usually lobular and associated with endosteal scalloping that may be quite extensive and deep in this location. A calcified matrix with typical “arcs and rings” or “pebble” appearance confirms the diagnosis of a chondroid lesion ^[5]. Malignant transformation might be considered when a previously asymptomatic cartilage tumor becomes painful, the enchondroma grows more quickly, or radiographic analysis shows suspicious alterations [7,8]. While enchondromas can occur in the metaphysis, diaphysis, or epiphysis of the hand’s tubular bones, or they might cover the entire phalanx, they are typically observed in the long bones’ metaphysis ^[9]. The definitive examination requires a histopathological examination. Takigawa has advanced a radiographic categorization scheme for chondromas that includes five categories: (1) “central, (2) eccentric, (3) associated (i.e., multiple lesions in the same bone in distinct locations), (4) polycentric (i.e., including the majority of the medullary canal of the tubular bone), and (4) along with  giant form” ^[10]. A monostotic lesion is another term for a solitary lesion, while polyostotic enchondromas or multiple enchondromatosis are terms used to define multiple lesions that affect different bones ^[8]. Osteomyelitis, tuberculosis, and coccidioidomycosis infections may resemble hand enchondroma. Like enchondromas, ABCs along with simple bone cysts are well-defined, lucent lesions having cortical extension. However, ABCs do not show intralesional calcifications and usually have an effervescent look. Intraosseous epidermal inclusion cysts, which are post-traumatic keratin-filled cysts, might resemble enchondroma, especially in the distal phalanx. Bone GCTs are benign lesions with the potential to spread to different body areas. Although intralesional calcifications are rarely observed, they usually exhibit cortical expansion and disintegration, with or without involvement of the surrounding soft tissues. In addition, spindle cell hemangioma as well as hemorrhagic epithelioid hemangioma can present deceptively like enchondroma. An epiphyseal lesion ought to cause speculation of chondroblastoma, even though the hand is an uncommon location of this tumor ^[8]. A well-defined, somewhat hypocellular specimen having lacunae-bound, dark-stained chondrocytes lodged in a cartilaginous matrix is what microscopically identifies enchondroma (Fig. 9). There is limited engulfment of the nearby cortical as well as lamellar bone.

Chondrosarcoma is the primary histologic differential diagnosis, characterized by a higher number of binucleated chondrocytes and a more cellular appearance than enchondroma. Furthermore, mucoid alterations, pleomorphism, trapping of the host bone by tumor, cortical degradation, and uneven cellular distribution are characteristics that set chondrosarcoma apart.

Enchondroma, the most prevalent benign tumor of the hand, is distinguished by the presence of lobules of hyaline cartilage and is typically present in the metaphyseal region of tubular bones. This case underscores the importance of timely diagnosis through imaging and histopathology to differentiate enchondromas from other potential lesions or malignancies. Surgical management, involving lesion excision and autograft reconstruction, demonstrated excellent results, enabling complete healing and restoration of function within 20 weeks post-operatively. This approach highlights the efficacy of precise surgical techniques combined with structured post-operative rehabilitation in achieving optimal patient outcomes.

Although enchondroma is the most common tumor of hand it is rare and most often is an incidental finding. It must be investigated through proper radiograph, MRI, and histopathological examination. The treatment includes excision of tumor and bone grafting which results in excellent recovery and finger movement of the patient and rare recurrence of the tumor.