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Abstract

  1. Top of page
  2. Abstract
  3. Case Report
  4. Discussion
  5. Acknowledgments
  6. References

Soft tissue chondroma is a rare benign tumor of the cartilage. It occurs commonly in distal extremities of middle-aged patients. It is usually asymptomatic and grows slowly, making early diagnosis difficult. We report a 10-year-old patient with a 1-year history of a subungual soft tissue chondroma on her left fifth finger. The lesion arose from nail bed and distal nail matrix, resulting in nail dystrophy. Magnetic resonance imaging revealed a soft tissue tumor in the subungual region and soft tissue chondroma was diagnosed, based on histopathologic findings. Dermatologists should consider soft tissue chondroma in the differential diagnosis of subungual tumors of children.

A soft tissue chondroma is a rare benign tumor that mostly occurs in the distal extremities [1]. It is a cartilaginous tumor without continuity with underlying bone or periosteum. Clinically it is a slowly growing nodular mass that usually arises in middle-aged patients [2]. Even though many patients have this tumor on their fingers, we herein present a case of a subungual lesion, a rarely affected area. We report the case of a soft tissue chondroma occurring in the subungual region of the finger with nail deformity in a child.

Case Report

  1. Top of page
  2. Abstract
  3. Case Report
  4. Discussion
  5. Acknowledgments
  6. References

A 10-year-old girl presented with a 1-year history of an asymptomatic mass and nail dystrophy on her left fifth finger. She denied a history of trauma. On examination, two longitudinal fissures and redness on the distal lunula were observed, along with a firm, immovable mass in the subungual area (Fig. 1A, B). Magnetic resonance imaging (MRI) revealed a 0.5-cm × 0.6-cm, well-demarcated, flat to oblong homogenous mass in the subungual region (Fig. 1C). The lesion was isointense relative to the skeletal muscle on T1-weighted images and hyperintense because of the high water content on T2-weighted images. No abnormal signal intensity was observed in the adjacent bone or terminal band of the extensor tendon. Excision and biopsy of the tumor was performed. After total nail extraction, the nail bed and matrix were incised longitudinally to expose the mass. Gross examination revealed a white, firm, solid tumor without connection to the underlying bone (Fig. 1D). The tumor was carefully resected with curettage of the surrounding tissues. Histopathologic examination showed hyaline cartilage with variable cellularity of chondrocytes with plump nuclei (Fig. 2). There was no mitosis or nuclear pleomorphism. Based on these findings, a diagnosis of soft tissue chondroma was made. There were no signs of tumor recurrence at the 3-month follow-up.

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Figure 1. (A, B) There are two longitudinal fissures and focal trachyonychia with redness on the distal lunula of the left fifth finger. (C) T2-weighted sagittal image revealed a 0.5-cm × 0.6-cm, flat, oblong-shaped mass in the subungual region (arrow) and its transverse view (upper imaging). (D) The tumor is exposed under the incision in the nail bed (arrow).

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image

Figure 2. (A) Histopathology showing a fragment of hyalinized cartilage with grouped chondrocytes (haematoxylin and eosin, 40×). (B) Under high magnification, chondrocytes have plump nuclei without mitosis or nuclear pleomorphism (haematoxylin and eosin, 400×).

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Discussion

  1. Top of page
  2. Abstract
  3. Case Report
  4. Discussion
  5. Acknowledgments
  6. References

Chondroma is a benign cartilaginous tumor that is classified into three types in accordance with the area of occurrence: enchondroma, periosteal chondroma, and soft tissue chondroma [3]. Soft tissue chondroma is a tumor of cartilage without any connection to the underlying bone. It can occur in patients of any age, but is most common in middle-aged patients [2]. In our case, the patient was only 10 years old, much younger than other reported cases [3-6]. To our knowledge, childhood cases have not been previously reported. In addition, because her tumor was small, there was no convex nail deformity, as is characteristic in other reported patients [3-6].

More than 80% of patients have soft tissue chondroma on the hands, especially on the fingers [7, 8]. Only a few cases of subungual soft tissue chondroma have been reported, although some cases of enchondroma or periosteal chondroma on the subungual area have been described [9, 10]. Even these cases are likely to be inaccurate because some of the earliest written reports did not demonstrate histological details or MRI findings [4].

Because soft tissue chondromas are usually asymptomatic and grow slowly, it is difficult to make an early diagnosis. Clinically these small, firm or rubbery subungual masses have to be differentiated from soft tissue chondromas, glomus tumors, exostosis, and others [6, 11]. Radiographs and MRI are useful in the initial evaluation of these tumors, identifying bony abnormalities and the contour of the soft tissues. Contrast imaging with MRI can further specify the nature and extent of the tissues involved [12]. Radiographs of soft tissue chondromas reveal an extraskeletal soft tissue shadow with irregular calcification [7]. MRI shows high signal intensity on T2-weighted images and intermediate signal intensity on T1-weighted images, as found in this case [12]. There is no periosteal reaction or destructive change in the bone, which are characteristics of periosteal chondroma and enchondroma. Bony exostosis demonstrates broad-based trabeculated bone with distal flare, and glomus tumor shows strong enhancement of the mass within a low-signal capsule [9, 12]. Generally it is not difficult to differentiate soft tissue chondromas from other digital tumors. Nevertheless, histologic confirmation is most accurate and reduces the potential for misdiagnosis.

Histopathologically, soft tissue chondromas show lobules of hyaline cartilage with calcification or ossification. Pathologic findings of high cellularity, pleomorphism, atypical mitosis, and some giant cells differentiate soft tissue chondroma from chondrosarcoma. Ki-67 immunohistochemical stain may be positive in malignant cases [13]. Although rare cases of malignant transformation of enchondroma into chondrosarcoma have been reported, to our knowledge there has not been any case of malignant transformation arising from a soft tissue chondroma [4, 14]. For this reason, treatment is recommended only for patients who have persistent pain or cosmetic concerns, such as nail deformity. After surgical removal, local recurrence is reported to be 17% to 18% [3]. Some studies have shown that curettage of the underlying sclerotic bone is necessary to prevent local recurrence of soft tissue chondroma [15].

Herein we report the first reported case of a soft tissue chondroma in a child. It is important that dermatologists be vigilant about persistent nail dystrophy, regardless of age, and consider soft tissue chondroma in the differential diagnosis of subungual tumors in children.

Acknowledgments

  1. Top of page
  2. Abstract
  3. Case Report
  4. Discussion
  5. Acknowledgments
  6. References

This article was supported by a basic science research program through the National Research Foundation of Korea, funded by the Ministry of Education, Science and Technology (2012046972).

References

  1. Top of page
  2. Abstract
  3. Case Report
  4. Discussion
  5. Acknowledgments
  6. References