Sclerosing dermatofibrosarcoma protuberans (DFSP): an unusual variant with focus on the histopathologic differential diagnosis

• Published in: International journal of dermatology Vol. 45; no. 1; pp. 59 - 62
• Main Authors: Sabater‐Marco, Vicente, Pérez‐Vallés, Ana, Berzal‐Cantalejo, Fernanda, Rodriguez‐Serna, Mercedes, Martinez‐Diaz, Francisco, Martorell‐Cebollada, Miguel
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01-01-2006; Blackwell Science; Blackwell Publishing Ltd
• Subjects: Biological and medical sciences; Biopsy, Needle; Dermatofibrosarcoma - diagnosis; Dermatofibrosarcoma - pathology; Dermatofibrosarcoma - surgery; Dermatology; Diagnosis, Differential; Follow-Up Studies; Humans; Immunohistochemistry; Male; Medical sciences; Middle Aged; Neoplasm Staging; Risk Assessment; Sclerosis - pathology; Skin Neoplasms - diagnosis; Skin Neoplasms - pathology; Skin Neoplasms - surgery; Treatment Outcome; Tumors of the skin and soft tissue. Premalignant lesions; Case study; Human; Skin disease; Anatomic pathology; Sarcoma; Dermatology; Malignant tumor; Dermatofibrosarcoma protuberans; Differential diagnostic
• ISSN: 0011-9059; 1365-4632
• DOI: 10.1111/j.1365-4632.2004.02340.x

A 59‐year‐old man presented with a 10‐cm × 8‐cm tumoral plaque with a superficial nodule in the interscapular region of the back (Fig. 1). The lesion had been growing for 25 years. As a cystic lesion was suspected, the superficial nodule was biopsied. The histopathologic diagnosis was low‐grade sarcoma with sclerosis. Two months after the initial biopsy, the lesion was completely excised, reaching the muscular fascia, with a 2‐cm margin and with a free graft.
1
Clinical aspect of the plaque in the lesion on the back
Formalin‐fixed paraffin‐embedded samples were submitted to histologic and immunohistochemical study (4‐µm paraffin sections); frozen tissue was submitted to electron microscopy.
For histopathology, sections were stained with hematoxylin and eosin. Immunohistochemistry was performed following standard avidin‐biotin immunoperoxidase procedures with primary antibodies for vimentin, CD34, smooth muscle‐specific actin, bcl‐2, S‐100, desmin, myoglobin, factor VIII, p53 (all from DAKO, Copenhagen, Denmark), HHF‐35 (Enzo Diagnostics, Farmingdale NY), cytokeratin (AE1/AE3) (Biogenex, San Ramon, CA), and factor XIIIa (Calbiochem Novabiochem Corporation, La Jolla, CA).
At low magnification, the histologic study of the initial tumoral nodule revealed a poorly circumscribed mesenchymal proliferation, with fibroblastic‐like neoplastic cells arranged in a fascicular and storiform pattern, admixed with extensive areas of sclerosis. At higher magnification, tumoral cells were spindle‐shaped with hyperchromatic nuclei and scant cytoplasm. In some areas, sclerosis was so evident that a keloid‐like pattern was seen (Fig. 2a). The surgical specimen showed a fibroblastic neoplastic proliferation infiltrating the dermis and hypodermis. In the dermis, cells were arranged in a storiform pattern, whereas in the hypodermis there was a honeycomb or lace‐like pattern (Fig. 2b). There were also cellular areas alternating with sclerotic areas, with transitional zones in between, in both the dermis and hypodermis.
2
(a) Keloid‐like hyalinization area in the initial biopsy; (b) surgical specimen of the hypodermis showing honeycomb pattern
The immunohistochemical study of the initial tumoral nodule and the surgical specimen showed that tumoral cells expressed vimentin, CD34 (Fig. 3), bcl‐2, HHF‐35, and smooth muscle actin. Neoplastic cells failed to show positivity with desmin, myoglobin, factor XIIIa, factor VIII, S‐100, cytokeratin (AE1/AE3), and p53.
3
CD34 positivity in tumoral cells in the initial biopsy
An ultrastructural study revealed spindle cells having an irregular contour with a well‐developed granular reticulum endoplasmic (REG) system in their cytoplasm, as well as some Golgi complexes and mitochondria. Also visible was the presence of many actin filaments and some myosin condensations (Fig. 4), characteristics of a fibroblastic cell with myofibroblastic differentiation.
4
Presence of many actin filaments (short arrow) and some myosin condensations (long arrow), characteristics of a fibroblastic cell with myofibroblastic differentiation
The final histopathologic diagnosis of the surgical specimen was sclerosing dermatofibrosarcoma protuberans. Two years after surgery, the patient is alive and well.