Resection and Reconstruction is the Procedure of Choice for Giant Cell Lesions of Small Bones: A Case Report and Literature Review

Background: Giant cell lesion of small bones (GCLSB), also known as giant cell reparative granuloma, is a rare tumor-like condition occurring in the small bones of the hands and feet. GCLSB lacks specic clinical, radiological, and histological manifestations. There are no standardized protocols for treatment. Case presentation: Here, we report a 16-year-old male with recurrent GCLSB in the proximal phalanx of the left thumb. The lesion was successfully resected with bone grafting. Conclusions: We summarized the characteristics of 33 reported cases of GCLSB from 1983 to date, including gender, age, lesion sites, recurrence, and treatment. We conclude that resection and reconstruction with curettage is the treatment of choice. Giant cell lesion of small bones (GCLSB) is an infrequent tumor-like condition occurring in the hands and feet. Also known as giant cell reparative granuloma (GCRG), GCLSB is dened by the World Health Organization as a lesion consisting of brous tissue with hemorrhage, hemosiderin deposits, irregularly distributed giant cells, and reactive bone formation 1 . Because the features of GCLSB lack specicity, diagnosis requires a combination of clinical examination, imaging, and pathology. At present, there is no standardized treatment for GCLSB, primarily because there are so few reports. We present a case of recurrent GCLSB of the phalanx treated with surgical resection. We discussed the clinicopathological features of the disease and its treatment and provided a review of the literature.


Background
Giant cell lesion of small bones (GCLSB) is an infrequent tumor-like condition occurring in the hands and feet. Also known as giant cell reparative granuloma (GCRG), GCLSB is de ned by the World Health Organization as a lesion consisting of brous tissue with hemorrhage, hemosiderin deposits, irregularly distributed giant cells, and reactive bone formation 1 . Because the features of GCLSB lack speci city, diagnosis requires a combination of clinical examination, imaging, and pathology. At present, there is no standardized treatment for GCLSB, primarily because there are so few reports. We present a case of recurrent GCLSB of the phalanx treated with surgical resection. We discussed the clinicopathological features of the disease and its treatment and provided a review of the literature.

Case Presentation
In August 2017, a 16-year-old male presented with swelling and pain of the left thumb. A lump the size of a ngernail with pain on palpation was found on the radial side of the left thumb. There was no previous history of trauma. He went to Central Hospital of Siping city in September 2017. Xray revealed a lytic expansile lesion of the proximal phalanx of the left thumb (Fig. 1). The patient was treated with curettage, 99.5% ethanol sterilization, and grafting in September 2017. Postoperative pathology identi ed giant cell reparative granuloma.
In July 2018, the patient presented with recurring swelling and pain of the left thumb. As the lump grew progressively, the patient came to our hospital in September 2018. Laboratory examinations (complete blood count, prothrombin time, partial thromboplastin time, and serum level of calcium) were within normal ranges. Magnetic resonance imaging (MRI) revealed a distended lesion in the proximal phalanx of the left thumb that presented with high signal intensity in in both enhanced T1-weighted and enhanced T2-weighted images (Fig. 2). The border was distinct and the cortex was intact. The surfaces of the joints were smooth. Subsequently, the proximal phalanx, interphalangeal joint, and metacarpophalangeal joint of left thumb were resected. Iliac bone measuring 3.0 x 1.0 x 1.0 cm was grafted. The interphalangeal joint was held in place longitudinally and cross-xed using two Kirschner wires. The stop point of the adductor pollicis was reconstructed at the base of the proximal phalanx. The hallux abductor brevis stop was sutured to the radial side of the metacarpophalangeal capsule (Fig. 2). Histological analysis revealed heterogeneous fusiform or broblast-like cells with occasional mitotic gures. Some fusiform cells were lled with lipid without de nite atypia. There were scattered multinucleated giant cells (Fig. 2). No clinical or radiographic evidence for a recurrent lesion was found at 17-month follow-up (Fig. 3). The palm-to-palm test of the thumb was negative (Fig. 3). Pinch strength was measured using the Biometrics E-LINK system (Biometrics Limited, US). The pinch strength of the left thumb was slightly lower than normal (Table 1). Using the AMA impairment guidelines, the analysis suggest that the left upper limb lost 12% of its function after surgery.

Literature review
We performed a Medline literature search to identify cases of GCLSB. English and non-English-language papers were searched in PubMed using a combination of terms: ((((((((metacarpal) OR (carpal bones)) OR (phalanx)) OR (metatarsal bones)) OR (tarsal bones)) OR (hand)) OR (foot)) AND (giant cell reparative granuloma)) OR (giant cell lesion of small bones). The search was carried out using the literature from 1983 to the present. The data available are summarized in Table 2. We were able to nd 33 patients (include this study) with 37 lesions. The 33 patients included 16 men and 17 women with a mean disease duration of 22.3 years (range 4.5 to 67 years). Most patients were in their second decade (48.5%) followed by the third (21.2%), rst (8%), fourth (9.1%) and fth decades (9.1%). The lesion occurred most often in a phalanx (17 lesions, 45.9%), followed by metacarpal (11 lesions, 33.3%), metatarsal ( ve lesions, 15.1%), carpel bones (three lesions, 9.1%), and calcaneus (one lesion, 3%). Pain (19 cases), swelling (12 cases), and pathological fracture (four cases) were the symptoms mentioned most often. Among the 38 lesion sites, 26 were treated with curettage, ten were treated with resection and two were treated with amputation. Recurrence (in nine lesions) occurred only after curettage that proceeded a second surgery. Five of the nine lesions were treated with resection, three were treated with curettage and one was treated with amputation ( Table 2). Regardless of the operation frequency, 19 lesions (51.3%) were nally cured with curettage, 16 were cured with resection (40.5%), and three were cured with amputation (8.1%).   Table 3 Collation and analysis of data in Table 2 Number  24 . Nevertheless, it remains to be determined whether this rearrangement is prevalent in GCLSB. Because GCLSB is not rare, both radiologically and histologically, it is necessary to strictly follow the principle of clinical-image-pathology to make appropriate treatment decisions.
To date, there have been no guidelines for treatment because of the low level of morbidity. According to our data in Table 2, surgeons tend to choose curettage and grafting. This results in minimal damage to function; however, it also carries the risk of recurrence. Phenol and ethanol were used by Yoshida et al. to reduce the recurrence rate 16 . In our case, ethanol did not prevent recurrence. The analysis shows that 36% of lesions recurred after curettage; however, none of resected lesions recurred. Only 51.3% of lesions were nally cured by curettage, while 43.2% of the lesions were cured by resection, and 5.4% of the lesions were cured by amputation (Table 3). Amputation is rarely chosen by surgeons. As it is an extreme form of surgery which lead to totally loss of function.
Resection and reconstruction is the treatment of choice. It not only cures the lesion without a second operation, but it also tends not to compromise function. Macdonald et al. reconstructed the lesion site with iliac crest bone grafting and fascial arthroplasty. His patient's grip strength and motion at metacarpophalangeal joint was preserved. 15 . For the young patient described in this report, the lesion occurred in the shaft of the proximal phalanx of the thumb. To prevent recurrence, we had to remove the proximal phalanx, interphalangeal joint, and metacarpophalangeal joint, and conduct joint fusion with bone grafting. Postoperative follow-up revealed slightly lower pinching power of the thumb. If we had tried to preserve the metaphysis and remove the diaphysis of phalanx with grafting during the rst operation, the proximal phalanx, interphalangeal joint, and metacarpophalangeal joint could be retained, and the function of thumb might be better preserved.

Conclusion
In summary, we report a case of a 16-year-old man with recurrent GCLSB that was successfully resected with bone grafting. We conclude that resection and reconstruction with curettage is the treatment of choice.
Abbreviations GCLSB, giant cell lesion of small bones; GCRG, giant cell reparative granuloma; MRI, magnetic resonance imaging Declarations Ethics approval and consent to participate Not applicable.

Consent for publication
Informed consent was obtained from the patient.

Availability of data and materials
All data generated or analyzed during this study are included in this published article.

Competing interests
The authors have no potential con icts of interest to disclose. study conception and design, data analysis or interpretation, paper writing or deciding to submit this paper for publication.

Authors' contributions
Jiannan Li wrote the initial draft. Zhan Zhang and Guangzhi Wu were the surgeon. Weizhong Zhang performed the pathological examination. All authors read and approved the nal manuscript.