Giant enchondroma recurrence of the proximal phalanx of the fifth finger: a case report

Enchondroma (EC) is a benign and cartilage-forming tumor that causes intramedullary lesions. Moreover, EC is the most common bone tumor in the phalanges and metacarpal bones of the hand, deforming the structure and causing pain and functional limitation. The management of this neoplasia is the surgical treatment and the approach that is well-accepted consists in the curettage followed by the void augmentation with biological or synthetic fillers. The results from surgery are usually good and the recurrence rate is low (2-15%). In this article we report a case of EC recurrence of the proximal phalanx of the fifth finger of the hand after curettage and grafting. The patient was treated with the amputation of the fifth ray according to the Tsuge technique, obtaining a satisfying clinical result.


Introduction
Enchondroma (EC) is benign tumor from cartilage origin, that mainly affects the skeleton of the hand and malignant transformation of solitary enchondroma is extremely rare (< 1%) [1]. In the context of enchondromatosis (Ollier disease and Maffucci syndrome) the risk of malignant transformation is increased up to 35% [2]. Often patients with EC are asymptomatic or with few symptoms and signs such as a localized painless swelling. For this reason, EC may be diagnosed during a routine physical examination, as an incidental finding on plain radiographs or in the event of a pathologic fracture commonly caused by minor trauma and favored by the presence of the tumor [3].
Conservative treatment through regular check-up and surgical excision using curettage are the two major treatment methods for EC.
Surgical treatment of this lesion is recommended for a histological diagnosis execution, as well as for the prevention of complications, such as progressive finger deformity, pathological fracture and tendon injuries [4]. Curettage and bone grafting have been the conventional methods of treatment. Other treatment approaches include curettage and filling of bone substitute, cementation and additional chemical treatment. Surgery outcome are usually successful and the recurrence rate is low (2-15%) [5]. We report a case of a giant EC recurrence of the proximal phalanx of the fifth finger of the hand (PP5th) after curettage and back-filling with calcium phosphate bone cement (CPC), treated with the amputation of the fifth ray according to the Tsuge technique.

Discussion
EC is a relatively benign medullary cartilaginous neoplasm with benign imaging features. In diaphyseal localizations the treatment of choice remains the complete emptying of the lesion, through a "window of the cortical bone" and subsequently curettage and grafting with allogenic bone, autogenous bone or synthetic bone substitutes [7].
Various recurrence rates were reported in literature with different treatments. In the retrospective review on 102 patients, Sassoon et al. observed a recurrence rate of 6% [8]. Whereas, Gaulke and Suppelna reported a recurrence rate of 14% in a long-term follow-up (mean, nine years) and all recurrences (3 patients) were discovered after 10 years from the surgery [9]. Further, Wolf et al. detected the presence of recurrence of 6.5% after treatment with curettage and application of CPC [10]. Amputation is performed when the EC evolves into chondrosarcoma, or in case of multiple relapses, in order to prevent malignant evolution of the disease.
In addition, amputation can be considered when bone deformity becomes so evident to compromise joint´s function. In our case, the patient has an EC recurrence after 5 years from the surgical treatment.
Because of pain and functional limitation of the fifth finger, we decide to perform an amputation of the fifth ray. Indeed, the lesion´s size prevented the correct movement of the fifth finger and the function of the whole hand. Amputation seemed to us to be the best choice to eradicate pain and prevent a possible new recurrence or malignant evolution. With regards to the best level at which surgical amputation should be performed, on both functional and cosmetic grounds, the complete removal of the fifth ray is preferable to the reshaping of the stump or to the disarticulation at the level of the metacarpophalangeal joint. An amputation abutment of the little finger at the level of the first phalanx has no functional significance and is unsightly. Moreover, the stump tends to be a hindrance in normal daily activities (i.e.: open and close a drawer, handle domestic utensils).

Conclusion
The simple curettage represents an effective option for the treatment of most hand EC. When recurrence affects the PP5th, the simple amputation of the finger can create difficulty on the functionality of the hand. As an alternative the amputation might include parts of the fifth metacarpal bone in order to improve hand movement and pain.

Competing interests
The authors declare no competing interests.