Dermatofibrosarcoma protuberans: an unusual presentation and a challenging case
Creators: name: Diaz-Cano, Salvador J.
name: E Craythorne
name: A Robson
name: J Salisbury
name: S Macfarlane
Publisher: name: figshare
Year: 2012
Subjects: Medicine
Cancer

description: Congenital dermatofibrosarcoma protuberans (DFSP) poses a diagnostic and therapeutic challenge. Not only is this low-grade fibrohistiocytic tumour extremely rare in childhood, but it may mimic benign-looking lesions such as vascular birth-marks leading to a delay in diagnosis. We report a four and a half year old boy who presented to the paediatricians at 6 months of age with a small frontal scalp swelling. This was thought clinically to be a bruise and his parents were reas-sured. His family moved to another part of the country and he re-presented at the age of 3 years to plastic surgery with the same persistent but enlarged lesion. At this point the clin-ical impression was of a sebaceous cyst and it was surgically excised. Histology, however, showed a pleomorphic spindle cell proliferation with a storiform architecture occupying the entire dermis and infiltrating into subcutaneous fat. Immuno-histochemistry was positive for CD34, and a diagnosis of incompletely excised DFSP was made. He was referred to our unit when the poorly defined tumour of the scalp measured 63 x 60 mm. Excision of the tumour by Mohs' micrographic surgery (MMS) using the fixed-tissue technique (slow MMS) was carried out with tumour-negative margins after two stages and 20 blocks. He remains free from recurrence at 10 months after surgery. DFSP is rare, with a high recurrence rate but low potential for metastasis, and usually presents in mid adult life on the trunk or limbs. Congenital DFSP is particularly rare with a predilection for the trunk and extremities. The initial clinical appearance of congenital DFSP is often a red-blue vas-cular looking macule or plaque, leading to the misdiagnosis of a vascular malformation, before progressing to a more nodular lesion. Treatment of DFSP is surgical. MMS is favoured over 2–3-cm wide surgical margins as the former offers histological margin control with likely lower recurrence rates and tissue conservation. The drawback of repeated general anaesthetic exposures for congenital DFSP may limit its use. Congenital DFSP of the scalp is a rare entity but given the locally aggressive nature of these tumours with a high potential for recurrence, early diagnosis and adequate surgical excision is advised. protuberans (DFSP) is a rare, slow-growing, infiltrative skin tumour of intermediate malignancy, with a limited potential for metastasis but a high incidence of local recurrence. It arises in the dermis, subsequently invading deeper tissues. Due to its highly infiltrative growth pattern, DFSP often extends far beyond the clinical margins; this accounts for the high incidence of recurrence following stand-ard surgical excision. Even after wide excision with a 3-cm surgical margin and deep excision to fascia, as is recommen-ded, the reported incidence of recurrence varies from 11 to 20%. Mohs' micrographic surgery is increasingly being heral-ded for its improved recurrence rate of 0–6%. We report the rare and interesting case of a 47-year-old Jamaican lady who presented with a 4-year history of a large 3 cm, firm nodule on the right shoulder. Surrounding this, there were three smaller hyperpigmented plaques with features suggestive of dermatofibromas. All were separated by at least 5 cm of clinic-ally normal skin. The histology of the initial biopsies was vari-able, with DFSP and dermatofibroma patterns observed in different areas. Following multidisciplinary discussion, she underwent wide excision of the central nodule that was felt to be DFSP, and standard excision of the three satellite lesions. Similar histological variation was observed in these specimens; thus, a diagnosis of DFSP, with admixed features of dermato-fibroma, was made. On review of the pathology each of the satellite lesions were said to be clear at the margins. Explana-tions include the possibility of sampling error, skip lesions within the tumour, or that the tumours had arisen separately. The patient had a further wide excision, resulting in a large defect requiring grafting. Pathological review of the final sam-ple did not contain any residual DFSP. This case raises interest-ing questions regarding diagnosis and management of this rare presentation of DFSP. We discuss what value Mohs' micrographic surgery might have played in our patient, its usefulness in showing if these lesions were contiguous and the feasibility of its use in such a large lesion. DS-20 The 'lip switch' flap for correction of excessive shortening, following excision of squamous cell carcinoma of the lower lip.