Keywords
malignant cartilage tumor - chondrosarcoma - hand chondrosarcoma
Introduction
Chondrosarcomas are the second most common primary malignant bone tumors after osteosarcomas.[1] They are chondroid lesions and account for 9% to 10% of all primary malignant bone
tumors.[2]
[3]
[4] Chondrosarcomas appear between 40 and 80 years old,[2] mostly around the 5th and 6th decade of life.[2]
[3]
[4]
[5] The most common locations are the pelvis, proximal femur, and proximal humerus in
up to 70% to 75% of cases.[3]
[5]
[6] Of all chondrosarcomas, 0.5 to 3.2% occur in the hand,[2]
[3]
[5]
[6] and mostly are low-grade lesions. Hand chondrosarcoma dissemination is exceptional,
even in lesions with a high histological grade.[2]
[6]
[7]
Although they can be primary tumors, up to 88% of hand chondrosarcomas are secondary
to the degeneration of pre-existing lesions such as enchondromas and osteochondromas
or occur with multiple enchondromatoses.[1]
[2]
[5] They affect men in a 3:1 ratio[3] and the phalanges in up to 68% of cases.[2] The proximal phalanx is the most common site, and its involvement occurs in approximately
53% of patients.[2]
[6] In addition, there is a predominance of the little finger at 33%.[5]
[6]
Based on cellularity, matrix and nucleus features, and number of mitoses, there are
three chondrosarcoma grades:[1]
[3]
[8] low (grade I), intermediate (grade II), and high (grade III). Low-grade lesions
are the most frequent and characterized by moderate hypercellularity and atypia compared
with the high cellularity and pleomorphism from high-grade lesions.[5]
For chondrosarcomas, the challenge lies in their differentiation from a benign condition
(for instance, an enchondroma), especially if the lesion is low-grade.[1] As a result, emphasis is placed on a complete study, with clinical, imaging, and
histology as the cornerstones to determine the malignant origin of the lesion and,
then, choose the definitive treatment, ranging from curettage and bone graft to wide
resection (amputation) of the compromised area.[6]
Clinical case
A 70-year-old woman, painter, and pianist, hypertensive under treatment, had a long-standing
history of a tumor in the right little finger. She presented pain and increased volume
at the right little finger for 5 months. She did not report any history of trauma.
The physical examination revealed an increased proximal volume of a stony consistency
affecting the base and proximal third of the proximal phalanx. The patient presented
good mobility of adjacent joints and no neurovascular compromise. We requested a conventional
radiological examination ([Figure 1]) and, to rule out a potential pathological fracture, a magnetic resonance imaging
(MRI) with contrast ([Figure 2]).
Fig. 1 Radiograph of the right little finger showing a radiolucent geographic bone lesion
on the proximal half of the first phalanx, which inflates and thins the cortex, with
endosteal scalloping, no suspicious periosteal reaction, and a non-aggressive appearance,
suggesting an enchondroma. There was a 5-mm bone fragment displaced upward and increased
volume of the regional soft tissue, possibly indicating a pathological bone fracture.
Fig. 2 Tumor lesion of the proximal phalanx of the little finger. Its characteristics and
the previous radiographic study indicate a chondroid tumor with malignancy signs resulting
from its extraosseous extension (chondrosarcoma) with no involvement of adjacent joints.
Since the study highly suggested a malignant lesion, we requested a chest computed
tomography (CT) scan, which showed no evidence of dissemination. After discussing
the case with the Oncology Committee from our institution and the Mayo Clinic, we
decided on a wide excision instead of an excisional biopsy. Since the involvement
of the proximal phalanx was almost complete, an excisional biopsy would virtually
be an amputation of the finger, leaving it dysfunctional and with no bone support.
The biopsy result confirmed the diagnosis of a well-differentiated grade I chondrosarcoma
and demonstrated the free margins.
Later, the patient presented an ulnar subluxation of the extensor tendon of the fourth
finger with mild symptoms. Its treatment consisted of conservative therapy and the
construction of a supportive orthosis. Three months after surgery, the patient resumed
her musical activity. After 1.5 years, there was no evidence of metastases ([Figure 3]).
Fig. 3 Postoperative follow-up radiograph (1.5 years later). Amputation at the fifth metacarpal
base level with no evidence of recurrence.
Discussion
Differentiating chondrosarcoma from an enchondroma is a considerable challenge, even
more so if the malignant tumor is low grade since they are similar in imaging and
histological features.[5] As a result, combining clinical interpretation with imaging and histopathological
studies is essential.[5]
[9] In this context, a histologically benign lesion could be considered malignant if
the imaging suggested it, while an imaging-benign tumor would be interpreted as malignant
if the clinical examination, histological findings, or both suggested it.[9]
[10] Making this difference is fundamental not only for diagnostic clarification but
determining appropriate treatments and reducing recurrence rates.[5]
Clinically, malignancy-suggestive signs include a progressive volume increase and
pain (a potential pathological fracture), and up to 10% of cases are asymptomatic.[2]
[6] For imaging, it is important to complement conventional radiology with CT, MRI,
or both with contrast to characterize the lesion and its relationship with adjacent
structures. In these cases, cortical destruction or thinning, soft tissue involvement,
periosteal reaction, and intralesional calcifications (“popcorn-like lesions”) suggest
malignancy.[2]
[3]
[6]
Regarding histology, it is worth mentioning that chondromas have high cellularity
and more nuclear atypia than in other parts of the body.[2] As a result, the microscopic appearance alone does not confirm the diagnosis. However,
a sample with abundant cartilaginous matrix, hypercellularity, bulging nuclei, binucleated
cells, and bone trabeculae entrapment suggests chondrosarcoma.[3]
Most chondrosarcomas are reportedly resistant to chemotherapy and radiotherapy.[1]
[2]
[6]
[9] As such, their treatment of choice is surgery, and the type of surgical intervention
is a matter of debate. Arguably, in a locally aggressive disease with exceptional
dissemination potential,[5] intralesional curettage plus bone graft is an alternative in low-grade, central
chondrosarcomas with no cortical involvement, sparing the body segment and its function
(especially in thumb injuries). This therapeutic alternative has a higher recurrence
rate,[1]
[2]
[6]
[11] ranging from 6% to 60%[1]
[6]
[11] compared with more aggressive management. On the other hand, to avoid the possibility
of local recurrence and dissemination and as an alternative for definitive treatment,
wide resection (amputation) is another option, as in this case, in which incisional
biopsy can lead to diagnostic error and an excisional biopsy (with intralesional curettage)
was not a good alternative since it would have left a dysfunctional finger with no
bone support. For high-grade lesions (II or III), with severe function-altering deformity,
extension to soft tissues, neurovascular compromise, and radiological and/or clinical
signs suggestive of aggressiveness, wide excision is more acceptable, always trying
to preserve the functionality and aesthetics.[1]
[2]
[3]
[5] The amputation must occur in the healthy tissue, sparing the lesion and removing
the tissue from the biopsy site.[2] In addition, it is worth mentioning that adequate follow-up is always required to
identify potential recurrence or dissemination, especially if treatment is more conservative.[3]
Conclusion
A hand chondrosarcoma is a rare condition with a low capacity for metastasis and high
recurrence rates, especially with insufficient treatments. The definitive diagnosis
is challenging, particularly when differentiating benign and low-grade malignant lesions.
As a result, it is essential to contextualize the clinical picture with the imaging
and histological findings. In some situations, intralesional curettage may be appropriate,
but wide excision still has a role in local tumor control.
