dermatofibrosarcoma protuberans, polymophic, page1

DERMATOFIBROSARCOMA PROTUBERANS THAT IS POLYMORPHIC

There is evidence that dermatofibrosarcoma protuberans (DFSP) is composed of some type of spindle cell of the peripheral nerve unit rather than of ordinary fibroblasts. Diverse mophologic patterns are encountered in other tumors of such derivation (malignant peripheral nerve sheath tumors, malignant schwannomas, Triton tumors, ossifying fibromyxoid tumors, etc.), so it is not surprising that diverse patterns are found in occasional examples of dermatofibrosarcoma protuberans. Therefore, a small biopsy of a polymorphic dermatofibrosarcoma protuberans may be very misleading.

This large skin tumor developed over a 10 year period on the chest of a 50 year old white female. At surgery, this was found to extend to the chest wall.

Mitoses were rarely found in this tumor.

This case is presented to illustrate some of the many patterns that can be seen in this type of tumor. Due to the number of photomicrographs, the case will be broken down into several pages. The slides were kindly provided by Matt Kershisnik, M.D..

A very low power view (direct scan of the glass slide) of one edge of the tumor. The tumor begins to the right side of the arrow. The tumor immediately to the right of the arrow is no thicker than the normal dermis. This has been described as 'atrophic dermatofibrosarcoma protuberans'. The usual degree of dermal thickening is seen to the right of the 'atrophic' area.The pattern of infiltration of the fat (honeycomb pattern) is very characteristic of DFSP but can be seen in fibrous hamartomas of infancy and a few other tumors.

A medium power view taken from the area just to the right of the arrow. Spindle cells are increased in number, but this area would be indistinguishable from a dermatofibroma.

A low power view taken from an area more to the right of the above picture. Lentiginous hyperpigmentation and acanthosis of the type found over many dermatofibromas are present. This combination can be seen, uncommonly, over other spindle cell tumors. There is a slight increase in the amount of tissue mucin. Increased tissue mucin can be seen in DFSP but also, rarely, in dermatofibromas.

A low power view that is representative of the more cellular portion of the tumor as seen in the dermis and subcutis. Cellular storiform (starburst) figures are characteristic of DFSP but can be seen in other settings. Hypercellular storiform figures, when combined with the honeycomb pattern of infiltration of the fat, are virtually diagnostic for DFSP.

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	A very low power view (direct scan of the glass slide) of one edge of the tumor. The tumor begins to the right side of the arrow. The tumor immediately to the right of the arrow is no thicker than the normal dermis. This has been described as 'atrophic dermatofibrosarcoma protuberans'. The usual degree of dermal thickening is seen to the right of the 'atrophic' area.The pattern of infiltration of the fat (honeycomb pattern) is very characteristic of DFSP but can be seen in fibrous hamartomas of infancy and a few other tumors.
	A medium power view taken from the area just to the right of the arrow. Spindle cells are increased in number, but this area would be indistinguishable from a dermatofibroma.
	A low power view taken from an area more to the right of the above picture. Lentiginous hyperpigmentation and acanthosis of the type found over many dermatofibromas are present. This combination can be seen, uncommonly, over other spindle cell tumors. There is a slight increase in the amount of tissue mucin. Increased tissue mucin can be seen in DFSP but also, rarely, in dermatofibromas.
	A low power view that is representative of the more cellular portion of the tumor as seen in the dermis and subcutis. Cellular storiform (starburst) figures are characteristic of DFSP but can be seen in other settings. Hypercellular storiform figures, when combined with the honeycomb pattern of infiltration of the fat, are virtually diagnostic for DFSP.