Abstract
A 15-year-old asymptomatic girl was found to have a large left lower chest wall mass associated with chest wall invasion on an opportunistic chest radiograph. The tumour was excised and shown to be a clear cell sarcoma. Adjuvant chemotherapy was administered and she was disease free at her 10 month follow up.
BACKGROUND
This is a very rare cause of chest wall tumour.
CASE PRESENTATION
A 15-year-old girl that had plain chest x ray as part of a routine medical examination was found to have a large left lower chest wall mass associated with rib destruction that was later shown to be painless and non-palpable (fig 1A). Chest CT revealed a 7×11 cm pleura based mass located in the left lower thorax and featured multiple rib destruction and downward depression of the left hemidiaphragm (fig 1B).
Figure 1. (A) Chest plain film revealing a large, well defined left chest wall tumour with obvious rib destruction.
(B) Thoracic CT revealing a large expansile tumour associated with osteolytic and sclerotic changes to a number of the patient’s ribs.
Direct inspection of the lesion during video assisted thoracoscopic surgery was undertaken to ensure neither pleural seeding nor pulmonary or diaphragm invasion. Following this procedure, wide excision of the chest wall tumour was then performed with thoracic cage reconstruction using a titanium mesh.
INVESTIGATIONS
CT guided biopsy revealed a lesion with clusters of melanin–laden tumour cells. These tumour cells were positive for HMB-45 and S-100 protein immunohistochemically. The cytoplasmic pigments could be bleached by superoxidative agent and were positive by Fontana Masson stain, consistent with melanin pigments in nature. The skin overlying the tumour was intact, and the tumour was impalpable. Thorough skin examination over her whole body by an experienced dermatologist did not reveal any suspicious skin lesion. No other abnormality was demonstrated on whole body image studies.
Grossly, the melanoma-like tumour had invaded into the sixth to ninth ribs, adjacent intercostal muscles and overlying chest wall muscles (fig 1A). Microscopically, the tumour consisted of nests and short fascicles of fusiform or polygonal cells with a clear to granular eosinophilic cytoplasm, expanding the parietal pleura with abundant intracellular and extracellular melanin pigmentation (fig 1B). Focal amelanotic tumour cell nests were also present. Immunohistochemically, the tumour cells were reactive to HMB-45 and S-100 protein. The diagnosis of chest wall clear cell sarcoma, formally known as malignant melanoma of soft parts, was then confirmed.
DIFFERENTIAL DIAGNOSIS
Differential diagnoses include synovial sarcoma, fibrosarcoma, epithelioid form of malignant peripheral nerve sheath tumour, spindle cell melanoma and renal cell carcinoma. One of the main differential diagnoses for clear cell sarcoma is metastatic malignant melanoma, but this was excluded in our patient because no mucocutaneous lesion suggestive of this diagnosis could be found.
TREATMENT
Wide excision of the chest wall tumour was performed with thoracic cage reconstruction using a titanium mesh. Four courses of adjuvant chemoradiotherapy were then administered.
OUTCOME AND FOLLOW-UP
The patient was disease free at her 10 month follow-up.
DISCUSSION
Clear cell sarcoma is a rare malignant soft tissue neoplasm histologically composed of nests or fascicles of cells featuring abundant pale staining or clear cytoplasm.1–3 As a consequence of the tumour’s close histological kinship with malignant melanoma, Chung and Enzinger proposed the name “malignant melanoma of soft parts” for this tumour type in 1983.1 Such a neoplasm occurs mainly among young adults aged 20–40 years as a painless mass or swelling located in the extremities associated with tendons or aponeuroses.1–3 Nevertheless, tumours do occur in the trunk on rare occasions.2,4,5
LEARNING POINTS
Clear cell sarcoma is a rare malignant soft tissue neoplasm
Clear cell sarcoma could present as a large chest wall tumour in asymptomatic young adults and should be listed in the differential diagnoses.
Early diagnosis and wide excision are essential for a favourable outcome of this tumour.
Acknowledgments
This article has been adapted with permission from Chen K-C, Lin W-C, Lee Y-C, Chen J-S, Hsu H-H. A large chest wall tumour in an asymptomatic 15-year-old girl. Thorax 2008;63:41.
Footnotes
Competing interests: None.
REFERENCES
- 1.Chung EB, Enzinger FM. Malignant melanoma of soft parts. A reassessment of clear cell sarcoma. Am J Surg Pathol 1983; 7: 405–13 [DOI] [PubMed] [Google Scholar]
- 2.Parasuraman S, Rao BN, Bodner S, et al. Clear cell sarcoma of soft tissues in children and young adults: the St. Jude Children’s Research Hospital experience. Pediatr Hematol Oncol 1999; 16: 539–44 [DOI] [PubMed] [Google Scholar]
- 3.Kawai A, Hosono A, Nakayama R, et al. Clear cell sarcoma of tendons and aponeuroses: a study of 75 patients. Cancer 2007; 109: 109–16 [DOI] [PubMed] [Google Scholar]
- 4.Suehara Y, Yazawa Y, Hitachi K, et al. Clear cell sarcoma arising from the chest wall: a case report. J Orthop Sci 2004; 9: 171–4 [DOI] [PubMed] [Google Scholar]
- 5.Hersekli MA, Ozkoc G, Bircan S, et al. Primary clear cell sarcoma of rib. Skeletal Radiol 2005; 34: 167–70 [DOI] [PubMed] [Google Scholar]