An 11 year old child is referred by dermatology for surgical removal of a lesion on the left side of the back pictured below. The family reports that the child had a lesion in the area since birth. They note that it appears that a second lesion has developed over the last year. This lesion has become more nodular in appearance with time. The dermatologist had performed a punch biopsy that showed a spindle cell neoplasm with irregular spindle cells filling the reticular dermis that stained positive for CD34. What is the best next step in the management of this child?

 

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[size=20px]a Observation

 

b Excisional biopsy with no margin

 

c Wide local excision

 

d Wide local excision, sentinal lymph node biopsy

 

e Ultrasound of the lesion Discussion

 

 

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C

C

D

E

E

Correct answer

C Wide local excision

 

This child presents with a dermatofibrosarcoma protuberans (DFSP) based upon the pathologic findings of spindle cells in the reticular dermis and the immunohistochemical staining for CD34.

 

DFSP is the most common dermal sarcoma. It has an incidence of 4.2 cases per million per year in the United States, with the number of reported cases increasing steadily over the last decades due to better recognition and improvement in ancillary diagnosis. The peak age of occurrence is typically between 25 and 45 years. However, pediatric cases make up about 6% of reported cases and it has been reported in children of all ages. There is a slight male preponderance. The most common area of involvement is the trunk (40-50%) followed by proximal extremities (30-40%) and head and neck (10-15%). The tumor arises within the dermis and subsequently infiltrates subcutaneous tissues. Patients typically describe a long history (ranging from months to several years) of a slowly growing indurated dermal plaque or nodule, with subsequent nodules appearing at later stages. Many patients describe a rapid growth phase following this period of relative quiescence.

 

Dermatofibrosarcoma protuberans are associated with high rates of local recurrence, especially if incompletely excised (with reports varying from 20% to 50% in adults and 0-13% in children). Metastasis occurs in fewer than 5% of patients and often follows multiple recurrences. The lungs are the most frequent site of distant metastasis, whereas nodal metastases are rare. This high recurrence rate is in part due to the fact DFSP tends to grow in an irregular shape that makes it difficult to remove completely. There is debate in the literature about the appropriate margin with ranges from 2 cm to 5 cm noted to prevent recurrence. A recent meta-analysis found that excision with < 3 cm surgical margin exhibited an increased risk of poor DFSP prognosis (high recurrence rate and increasing positive margin rate). Recent studies have also looked at the use of Mohs surgery to ensure complete removal at the time of wide local excision. This child presents with a DFSP of the trunk. Wide local excision with a margin of 3cm to ensure an R0 resection is appropriate. Ultrasound would not provide additional information and observation is not appropriate in this case. Due to the high local recurrence rate simple excisional biopsy is not indicated. Metastatic disease is rare and typically not through lymphatic spread - sentinel lymph node biopsy is therefore not indicated.