Dermatofibrosarcoma protuberans presenting in infancy and childhood Dermatofibrosarcoma protuberans (DFSP) is a not uncommon low-grade cutaneous sarcoma of uncertain histogenesis, which typically arises in early to middle adult life. Traditionally, it is regarded as extremely uncommon in infants and children, and this diagnosis may therefore easily be overlooked in young patients. Eight such cases (representing 5.9% of the available DFSPs on file) are presented of which two were congenital. Age range at presentation was 14 months to 12 years. Five arose on the trunk. Most had originally been mistaken for unclassified sarcoma, a fibromatosis, or diffuse neurofibroma. The histologic features were entirely comparable to the more usual adult cases except that all had a plaque-like, rather than nodular, growth pattern. Short-term follow up has revealed no recurrences. DFSP is not so rare in childhood and warrants wider recognition in order to ensure appropriate treatment. McKee PH, Fletcher CDM. Dermatofibrosarcoma protuberans presenting in infancy and childhood. J. Cutan Pathol 1991: 18: 241-246.

Dermatofibrosarcoma protuberans is a not uncommon low-grade malignant tumor of probable fibroblastic derivation. It is associated with a high recurrence rate but low metastatic potential. This neoplasm is usually regarded as occurring in young adults and the middle-aged, and as such there is often a reluctance by pathologists and clinicians to countenance this diagnosis in infants and young children. In this paper, the features of eight cases of dermatofibrosarcoma protuberans arising in infants and children are presented, in order to draw attention to such lesions in this age group.

P. H. McKee, C. D. M. Fletcher Department of Hisfopafhology Sf, Thomas's Hospifal (UMDS) London, England

C, D, M, Flefcher, Departmenf of Hisfopafhology, Sf, Thomas's Hospital, London SE1 7EH, England, Accepfed Ocfober 30, 1990

were studied immunohistochemically using the ABC technique, and antibodies to the following antigens were applied: vimentin (Dako, monoclonal, dilution 1/20), S-100 protein (Dako, polyclonal, dilution 1/2000), smooth muscle actin (Sigma monoclonal IA4, dilution 1/16000), and epithelial membrane antigen (EMA) (Dako, monoclonal, dilution 1/1000). The primary antibodies were incubated at room temperature for 1 h. Diaminobenzidine (DAB-0.6%) was used as the chromogen. Appropriate controls were used throughout. Clinical features

Material and methods

All cases of dermatofibrosarcoma protuberans (DFSP) in the files of the Department of Histopathology, St Thomas's Hospital, received between 1939 and 1989, have been reviewed. A total of 136 cases have been identified, of which eight (5.9%) presented before the age of 13 years. Of these, three were routine surgical specimens and five were received in consultation by the authors. All eight cases were fixed in 10% formalin and routinely processed. Four micron sections were cut and stained with hematoxylin and eosin. All cases ](> (Uitancous I'alliology

Five of the patients were girls and three were boys (Table 1). The site of the lesion was variable; three were on the back, two were on the shoulder, and one each was on the buttock, upper arm, and foot. Clinically, the lesions were usually described as a fiattened or atrophic, pale to red-blue plaque. The duration of the tumors ranged from six months to 'years'. The tumors were all slowly growing. Two lesions were present at birth. One (Case 1) arose at the site of a previous vaccination. There was no evidence of metastasis at the time of diagnosis. All patients were treated solely by surgery with wide 241

McKee & Fletcher Table 1. Clinical features of 8 cases of juvenile DFSP. Case no.

7 years 14 monfhs 12 years 9 years 6 years 5 years 10 years 10 years

Sex Sife F M F Ll_

1 2 3 4 5 6 7 8

Age

M M F F

Upper Arm Lower Back Back Shoulder R Shoulder Back Buffock Forefoof

Pre-op durafion

Follow up durafion

6 monfhs 3 monfhs 'years' 'years' Congenifal Congenifal 2,5 years 'years'

2 years 20 monfhs 18 monfhs 6 monfhs 9 monfhs 2,5 years N/A N/A

N/A = Information nof available.

re-excision when necessary. Insufficient follow up data is available for meaningful interpretation, but no lesion has recurred to date.

Histopathology All of the tumors were devoid of a capsule and were composed of spindle cells arranged in a well-defined and uniform storiform pattern. The tumors were principally arranged as a broad, flattened dermal plaque but invariably infiltrated the underlying subcutaneous fat (Figs. 1,2). The epidermis was normal in five cases, acanthotic in one, and ulcerated in two. A Crenz zone of papillary dermal sparing was evident in seven of the cases. In two cases, the tumor showed a focal fascicular pattern (Fig. 3), and in four there were central foci of scarring. Three tumours showed focal myxoid change. The tumor cells were uniform and had oval or fusiform vesicular nuclei with inconspicuous nucleoli (Fig. 4). Mitotic activity ranged from one to five per ten high power fields (HPF) (1 HPF = 0.159 mm^). An infiammatory infiltrate consisting predominantly of plasma cells was present in five of the tumors, including the two ulcerated lesions. Giant cells were not a feature but occasional bland histiocytes were evident. In four tumors, there were conspicuous dilated vascular channels but hemosiderin pigment was absent. In two tumors, melanin-containing dendritic spindle cells were evident (the Bednar Variant) (Fig. 5). In none of the tumors were foci of frank fibrosarcomatous differentiation (herring-bone pattern) identified (see below). Tumor cells expressed vimentin in all cases but were negative for S-100 protein, epithelial membrane antigen, and smooth muscle actin. Internal positive controls were appropriately stained in all cases.

Darier and Ferrand in 1924 (1) and so-named by Hoffman in 1925 (2). It is typically described as a 'raised, firm, multinodular tumor, fixed to the overlying skin but movable over the deeper tissues. Most develop initially as plaque-like areas of cutaneous thickening, and a reddish to blue discolouration is frequently present' (3). Whereas DFSP may present at a wide variety of sites, the majority are centered about the trunk and proximal extremities. Early lesions are usually symptomless, but established tumors may be associated with pain, ulceration, and occasionally haemorrhage. Although the earlier literature relating to DFSP mentioned examples of childhood involvement (3—5), this has been largely overlooked in more recent publications such that Enzinger and Weiss (6) state that DFSP 'seldom occurs in childhood, and only rare reports have documented the tumor during childhood or at birth'. The concept that DFSP is a tumor of the third to fifth decades has thus been sufficiently reinforced that the five cases referred to us in consultation, although histoiogically quite typical, were a source of considerable concern to the referring pathologists who were reluctant to make the diagnosis of DFSP in a young child. It is therefore of some interest to note that this series of eight

Discussion Dermatofibrosarcoma protuberans (DFSP) was clearly delineated as a clinicopathologic entity by

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Fig. 1. A broad band of tumor fills the dermis and has extensively replaced subcutaneous fat in this field (X25),

Infantile dermatofibrosarcoma protuberans

Fig. 2. A typical monotonous storiform pattern was evident in each case, (XlOO),

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Dermatofibrosarcoma protuberans presenting in infancy and childhood.

Dermatofibrosarcoma protuberans (DFSP) is a not uncommon low-grade cutaneous sarcoma of uncertain histogenesis, which typically arises in early to mid...
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