Giant cell tumor of bone with H3F3B mutation: A case report

Abstract

Rationale: Giant cell tumor of bone is a locally aggressive and rarely metastasizing neoplasm that typically affects the ends of long bones or the axial skeleton of young to middle-aged adults. As many as 69% to 100% of giant cell tumors harbor H3F3A gene mutations, while H3F3B gene mutations have rarely been reported.

Patient concerns: A 53-year-old male patient who underwent right distal femoral tumor resection.

Diagnoses: Preoperative CT plain scan indicated giant cell tumor of bone with pathological fracture. Laboratory findings were as follows: serum calcium was 2.23 mmol/L (reference range: 2.1-2.55 mmol/L) and serum phosphorus was 1.35 mmol/L (reference range: 0.81-1.45 mmol/L).

Interventions: The histological morphology showed the typical features of a conventional GCT. The immunoprecipitation analysis results were as follows: H3.3G34W(-), H3.3G34R(-), H3.3G34V(-), and H3K36M(-). Sanger sequencing showed that the H3F3A and H3F3B gene mutations were wild type. The high-throughput gene sequencing results revealed the H3F3B gene mutations H3.3p.Gly35Trp and H3.3p.Val36Leu.

Outcomes: The patient was stable with no recurrence in 12 months follow-up.

Lessons: Giant cell tumor of bone with H3F3B gene mutations is extremely rare. In the pathological diagnosis of bone tumors, we need to analyze clinical presentation, imaging features, histology, immunophenotype, and cytogenetic/molecular alterations, in order to get a correct diagnosis.

Figure 1.

Plain scan CT showed an expansile and well-defined bone destruction in the right distal femur, without calcification, ossification shadow or sclerotic border. Multiple fracture lines were seen around.

Figure 2.

Postoperative pathological and immunohistochemical staining results. 2A Mass specimen. 2B Microscopically, the mass was composed of mononuclear stromal cells and osteoclast-like giant cells. HE 400×. 2Creactive/metaplastic bone formation were seen around the lesion. HE 100×. 2DTumor cells were negative for H3.3G34W. IHC 100×.

Figure 3.

A Sanger sequencing showed that the H3F3A gene was wild type. 3B Sanger sequencing showed that the H3F3B gene was wild type. 3C Genehigh-throughput sequencing results revealed H3F3B gene mutations, including H3.3p.Gly35Trp and H3.3p.Val36Leu.