Chondrosarcoma proximal tibia secondary to chondromyxoid fibroma: A rare case report

Abstract

Introduction

Benign cartilage tumours with malignant transformation are reported very few. Aiming to report a secondary chondrosarcoma in proximal tibia after chondromyxoid fibroma: a rare entity with limited experience of management.

Case presentation

we present a challenging case of secondary chondrosarcoma of proximal tibia in surgically managed chondromyxoid fibroma. Presented to us with recurrent swelling and pain in proximal leg. The diagnosis was confirmed on biopsy and high-grade chondrosarcoma was found. Multidisciplinary approach was taken and treated with neoadjuvant chemotherapy and surgical excision was done with biological reconstruction with fibular strut and iliac crest grafting and soft tissue coverage with medial gastrocnemius muscle flap. The patient achieved good functional outcome with no recurrence at 2-year follow-up.

Discussion

Benign cartilage tumours mistreated might result in recurrence or malignant transformation. Treatment strategies vary with grade of malignant cartilaginous tumours with low grade chondrosarcoma treated with extensive intralesional curettage followed by local adjuvant treatment and high grade managed with wide excision or amputation.

Conclusion

Even though chondromyxoid fibroma is uncommon and benign, it has a high chance of recurrence and perhaps developing into chondrosarcoma. For better results and to stop progression, appropriate surgical intervention are essential.

Highlights

• •Chondromyxoid fibroma (CMF) is a rare benign cartilage tumour with a high recurrence risk.
• •Malignant transformation into chondrosarcoma occurs in 1 %–2 % of cases.
• •Preoperative MRI and biopsy confirmed aggressive features of chondrosarcoma.
• •Multidisciplinary approach involving chemotherapy, wide resection, and reconstruction with fibular graft
• •Successful limb salvage surgery with negative margins and intercalary reconstruction

1. Introduction

Chondromyxoid fibroma (CMF) is a rare benign cartilage tumour, making up less than 0.5 % of bone tumours [1]. It typically affects the metaphysis of long bones, especially the proximal tibia and distal femur [2,3]. While generally benign, CMF has a high recurrence rate (20 %–80 %) with a small risk (1 %–2 %) of malignant transformation into chondrosarcoma [4,5]. Chondrosarcoma, a malignant cartilage-producing tumour, can arise from CMF or other benign cartilage tumours. Symptoms include pain and sometimes a palpable mass, with higher-grade tumours showing aggressive bone destruction and a significant risk of metastasis. Low-grade chondrosarcoma is treated with curettage and local adjuvants, while high-grade cases typically require wide excision or amputation. Chemotherapy's role in treatment is still unclear for higher-grade tumours.

We report a case of secondary chondrosarcoma proximal tibia following surgically managed biopsy-proven CMF. The tumour was excised and biological reconstruction was done with the help of a multidisciplinary surgical team and post-operative recovery was uneventful. No recurrence was observed up to 2 years of follow up and the patient has excellent limb function.

Our work has been reported in line with the SCARE Guidelines 2023 criteria [6].

2. Case presentation

We present a case of a female in her mid-30s to our tertiary center with complaints of recurrent pain and swelling over left proximal leg for the past 2 years. She was an elsewhere operated case of CMF proximal tibia 4 years ago.

Initially, she had a history of pain and swelling in left leg 4 years ago which was gradually progressive. Seeking medical attention elsewhere, radiological investigations indicated a CMF of the left proximal tibia and the diagnosis subsequently confirmed by histopathological examination of core needle biopsy tissue. She underwent surgical intervention as resection of the tumour. Following surgery, the patient resumed her routine activities and remained asymptomatic for the subsequent years. However, after 2 years, she observed swelling in the same region where the surgical excision had taken place. Unlike the initial lesion, this swelling exhibited a rapid progression and was also accompanied by pain. She sought consultation at our hospital for further evaluation.

On examination, there was globular swelling of around 20 × 15 cm at proximal 3rd of tibia. The swelling displayed hard consistency with irregular surface and was tender on palpation. It was adherent to bone. The scar of previous surgery appeared healthy and distal neurovascular status was intact.

Preoperative and postoperative radiographs of the primary CMF (which had been treated elsewhere) were examined. The preoperative radiographs revealed an eccentric, expansive, meta-diaphyseal lesion affecting the proximal third of the tibia. The cortex appeared intact with periosteal thickening (Fig. 1). Plain radiograph of the recurrent lesion, taken on patient's presentation to our hospital, revealed lytic eccentric expansile solitary lesion in meta-diaphyseal region with cortical breach and sunburst periosteal reaction (Fig. 2).

Fig. 1.

Plain radiograph of left leg with knee showing eccentric, expansile, meta-diaphyseal lesion with intact cortex and periosteal thickening.

Fig. 2.

Plain radiograph of left leg with knee showing lytic, eccentric, expansile solitary lesion in meta-diaphyseal region with cortical breach and sunburst periosteal reaction.

MRIs showed a lytic expansile hyperintense lesion on T2 weighted image in meta-diaphyseal aspect of left proximal tibia. It showed choroid matrix and associated periosteum elevation. It was focally invading the left tibialis anterior and posterior medially and head of medial gastrocnemius (Fig. 3).

Fig. 3.

Magnetic Resonance Imaging of left leg showing A. Axial section T1-weighted showing expansile isointense lesion showing choroid matrix with cortical breach involving surrounding tissue (red arrow); B. Sagittal section T1-weighted; C. Coronal section T2-weighted showing hyperintense expansile lesion in meta-diaphyseal region of proximal tibia with periosteal elevation (red arrow). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Metastatic workup was done. PET-CT found metabolically active lesion involving proximal third of shaft of left tibia and few subcentimetric left popliteal lymph nodes suspicious of metastasis.

Core needle biopsy showed tissue with abundant cartilaginous matrix with chondrocytes embedded in lacunae. Chondrocytes exhibited moderate degree of atypia, coarse hyperchromatic nuclei and mitosis. Myxoid change, chondroid matrix and liquefaction and areas of necrosis was also noted.

Differential diagnosis of chondroid osteosarcoma and chondrosarcoma was made.

Following histopathological confirmation of the diagnosis, the multidisciplinary team at our hospital's tumour board, comprising experts from department of Orthopaedics, pathology and oncology, collaborated to determine the treatment strategy. A comprehensive plan was devised and patient was planned for neoadjuvant chemotherapy. Patient received 3 cycles of Adriamycin and cisplatin. Later was planned for the wide resection of the tumour, emphasizing the preservation of neurovascular structures.

The surgical approach was conducted through the previous surgical scar extending proximally and distally. On exploration, the tumour identified extending up to the subcutaneous plane, measuring 13 × 9 × 7 cm in size, displaying an irregular surface and exhibiting hard consistency. The neurovascular structures were successfully delineated from the tumour, and the resection was executed with 2 cm margin. Intraoperatively, negative margins were confirmed by frozen section histopathological examination. The intercalary reconstruction was done with ipsilateral vascularized double barrel fibular graft and ipsilateral iliac crest tricortical bone graft and fixation was done with 13-hole hockey plate (anterolaterally) and 9-hole medial T-plate. Soft tissue coverage was done by medial gastrocnemius muscle flap (Fig. 4).

Fig. 4.

Intraoperative clinical images showing curved incision marking over anterior aspect involving previous surgical scar (A) and lateral marking for fibular graft harvest (B), excised tumour with adhered skin (C), post fibula harvesting (D), fixation with bicolumnar plating and fibular strut graft (E) and medial gastrocnemius flap coverage (F).

Patient tolerated the surgery well, and the postoperative period transpired without any complications (Fig. 5). Histopathological examination of the excised tissue confirmed the presence of chondrosarcoma with tumour arranged in sheets and lobules embedded in abundant chondromyxoid matrix with moderated nuclear pleomorphism, hyperchromatic nuclei and indistinct cytoplasm. There were no tumour osteoid or atypical osteoblastic cells noted.

Fig. 5.

Post-operative plain radiograph of left knee with leg showing anteroposterior (A) and lateral (B) view.

The patient was discharged 9th day post-surgery, and during the follow-up appointments, the incision exhibited satisfactory healing. Patient received remaining chemotherapy on subsequent visits in oncology department. Physiotherapy was initiated, leading to the patient resuming partial weight bearing assisted walking and knee bending within 2 months.

A thorough follow-up regimen was implemented and plain radiographs were conducted during the monthly visits, revealing no signs of recurrence (Fig. 6, Fig. 7).

Fig. 6.

Follow up plain radiograph of left knee with leg showing anteroposterior and lateral view.

Fig. 7.

Follow up clinical images showing knee function with 0–130 degrees range of motion and active knee extension.

3. Discussion

CMF being a rare benign tumour of cartilaginous origin with commonest sites as long bones, usually affects the metaphysis of long bones [[1], [2], [3]]. Curettage alone, without packing the defect results in recurrence in about 20 %–80 % of the tumours [4]. The prognosis is promising with the risk of malignant transformation in 1 %–2 %, though a high recurrence rate of up to 80 % [5].

Chondrosarcoma lesions diagnosed as chondromyxoid fibroma, if under treated, can result in a worse prognosis later on. Moreover, recurrence of low-grade chondrosarcoma bears the risk for tumour progression toward a higher grade or even dedifferentiation, with a severe adverse prognosis.

In this case, patient had biopsy proven primary chondromyxoid fibroma of proximal tibia which later post primary surgery presented as secondary chondrosarcoma.

Chondrosarcoma is a malignant, cartilage-producing bone tumour. It is the least common bone cancer, with an estimated incidence of one in 200,000 persons [7]. Chondrosarcoma is the third most common primary malignant tumour of bone. Common cause of chondrosarcoma is presence of benign cartilage tumour [8]. Chondrosarcomas superimposed on preexisting benign cartilaginous neoplasms such as enchondroma or osteochondroma are referred to as secondary chondrosarcomas.

The most common skeletal location for conventional chondrosarcoma is the long tubular bones, accounting for approximately 45 % of cases. The femur is the single most commonly affected long bone, representing approximately 20 %–35 % of cases, followed in frequency by the tibia (5 %) [[9], [10], [11]]. Clinical symptoms are nonspecific, with pain being the most frequent symptom, occurring in at least 95 % of patients. A palpable soft tissue mass or fullness has also been described in 28 %–82 % of patients [12].

On radiology, more aggressive patterns of bone lysis (moth-eaten and permeative) may be seen with higher-grade conventional chondrosarcomas [12].

Grade I chondrosarcomas are lowly cellular, with an abundant hyaline cartilage matrix, and rarely metastasize [13]. In contrast, grade III chondrosarcomas are highly cellular, with a mucomyxoid matrix and mitoses, with metastases developing in 70 % of patients [14].

The effect of chemotherapy on grade II and III chondrosarcoma is difficult to assess because the number of reported cases is too low and reported series are mostly retrospective.

In low-grade chondrosarcoma, extensive intralesional curettage followed by local adjuvant treatment, for example, phenolization or cryosurgery (liquid nitrogen), and filling the cavity with bone graft has promising long term clinical results and satisfactory local control [15,16]. High grade chondrosarcoma is almost always treated with wide excision achieved by either amputation or resection of the tumour with limb salvage reconstruction [[17], [18], [19], [20]].

Author contribution

Sandeep Kumar Yadav: Project administration, Manuscript review and editing, operating surgeon (First author).

Aakash Kumar Choudhary: Manuscript original draft preparation, figure editing (Corresponding author).

Prabodh Kantiwal: Operating surgeon, manuscript proof-reading (Third author).

Shilpi Karmakar: Operating surgeon (Fourth author).

Poonam Elhence: Histopathological study (Fifth author).

Abhay Elhence: Manuscript proof-reading, Supervision (Sixth author).

Informed consent

Written informed consent was obtained from the patient. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Ethical approval

This study did not require ethical approval as it is a case report. However, informed consent has been obtained and can be provided on request. This study was exempted from ethical approval due to being case report by institute ethical committee of “All India Institute of Medical Sciences, Jodhpur”.

Guarantor

(First author) Sandeep Kumar Yadav.

Patient perspective

I was devastated when the pain and swelling returned after my initial surgery, and learning it had turned into cancer was terrifying. But the doctors here explained everything clearly, and though the chemotherapy and surgery were tough, I felt supported. After surgery, I was relieved to hear the tumour was gone. Recovery wasn't easy, but with my doctors' care and physiotherapy, I'm getting stronger. I'm grateful for the regular check-ups showing no recurrence, and overall, I'm satisfied and hopeful for the future.

Research registration number

NA.

Funding

This study did not receive any funding.

Conflict of interest statement

None. Authors declare that they have no conflict of interest.