Page 73 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 3-8 Malignant Growths

Dermatofibrosarcoma protuberans.
DERMATOFIBROSARCOMA Slow-growing, irregularly shaped tumor
PROTUBERANS

Dermatofibrosarcoma protuberans is a rare cutaneous
malignancy that is locally aggressive. The tumor is
derived from the dermal fibroblast, and it is not believed
to arise from previously existing dermatofibromas. Der-
matofibrosarcoma protuberans rarely metastasizes, but
it has a distinctive tendency to recur locally.
Clinical Findings: Dermatofibrosarcoma protuberans
is a slow-growing, locally aggressive malignancy of the
skin. These tumors are low-grade sarcomas and make
up approximately 1% of all soft tissue sarcomas. The Dermatofibrosarcoma protuberans.
tumor is found equally in all races and affects males Ill-defined, slow-growing tumor.
slightly more often than females. Most tumors grow so Red-orange plaque with nodular and
slowly that the patient is not aware of their presence for atrophic regions
many years. The tumor starts off as a slight, flesh-
colored thickness to the skin. Over time, the tumor
enlarges and has a pink to slightly red coloration. It
slowly infiltrates the surrounding tissue, particularly the
subcutaneous tissue. If the tumor is allowed to grow
long enough, the malignancy will grow into the fat
and then back upward in the skin to develop satellite
nodules surrounding the original plaque. This is often
the reason a patient seeks medical care. The tumor
tends to grow slowly for years, but it can hit a phase
of rapid growth. This rapid growth phase allows the High power. Malignant spindle cells make
tumor to grow in a vertical direction, and hence the up the bulk of the tumor.
term protuberans is applied. If medical care is not under-
taken, the tumor will to continue to invade the deeper
structures, eventually invading underlying tissue,
including fascia, muscle, and bone.
Dermatofibrosarcoma protuberans is, for the most
part, asymptomatic in the initial phases of the tumor.
As it enlarges, the patient may notice an itching sensa-
tion or, less frequently, a burning sensation or pain. As
the tumor enlarges, patients often notice tightness of
the skin or a thickening sensation; however, this devel-
opment is so slow that most patients ignore it for many
more months or even years. The differential diagnosis Low power. The tumor is seen invading the underlying Medium power. The storiform or
is often between dermatofibrosarcoma protuberans and subcutaneous tissue. The storiform pattern is seen cartwheel-arranged cells
a keloid or hypertrophic scar. The atrophic variant can throughout the dermal portions of the tumor.
often be confused with morphea. One clue to the diag-
nosis of dermatofibrosarcoma is the loss of hair follicles
within the tumor region. The adnexal structures are
crowded out by the ever-expanding tumor. If the tumor the platelet-derived growth factor B-chain (PDGFB) gene to differentiate dermatofibrosarcoma protuberans from
is allowed to enlarge enough, it will begin to outgrow with the collagen type I α1 (COL1A1) gene. This trans- the benign dermatofibroma, which has the opposite
its blood supply, and ulceration and erosions develop location directly causes the PDGFB gene to be under staining pattern. The stromolysein-3 stain is also used
thereafter. The tumors have ill-defined borders, and control of the COL1A1 gene. PDGFB is then overex- to help differentiate the two tumors; it is positive in
determining the extent of the tumor clinically can be pressed, and it drives a continuous stimulation of its cases of dermatofibroma and negative in cases of der-
challenging or impossible. A punch biopsy of the tumor tyrosine kinase receptor. matofibrosarcoma protuberans.
leads to the appropriate pathological diagnosis. Meta- Histology: Dermatofibrosarcoma protuberans shows Treatment: Because of the ill-defined nature of the
static disease is uncommon; however, local recurrence an infiltrative growth pattern. It invades the subcutane- tumors and their often large size at diagnosis, wide local
after surgical excision remains an issue. ous fat tissue. The tumor cells can be seen encasing excision with 2- to 3-cm margins is often undertaken.
Pathogenesis: The exact pathogenesis is unknown. adipocytes. The tumor is poorly circumscribed, and its Postoperative localized radiotherapy has been used to
By genetic chromosomal tissue analysis, these tumors borders can be difficult to distinguish from normal help decrease the recurrence rate. Imatinib has shown
have been found to have a reciprocal translocation, dermis. The tumor itself is made up fibroblasts arranged promise in dermatofibrosarcoma protuberans as a treat-
t(17;22)(q22;q13.1), which is believed to be pathogenic in a storiform pattern. These tumors stain positively ment before surgery to help shrink large or inoperable
in causing the tumor. The exact reason for this trans- with the CD34 immunohistochemical stain and are tumors. There has also been anecdotal success with the
location is unknown. The translocation causes fusion of negative for factor XIII. These two stains are often used use of imatinib in metastatic disease.

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 59