[522] Pleomorphic Dermal Sarcoma: Clinicopathologic Analysis of 32 Cases

Keith Miller, John R Goodlad, Thomas Brenn. Southmead Hospital, North Bristol NHS Trust, Bristol, United Kingdom; Western General Hospital and The University of Edinburgh, Edinburgh, United Kingdom

Background: If strict morphological and immunophenotypic criteria are applied, the behavior of atypical fibroxanthoma is almost entirely benign. However, tumors with similar pathological features but deep subcutaneous invasion, necrosis, lymphovascular or perineurial invasion may be associated with adverse outcome. Such tumors may be best regarded as pleomorphic dermal sarcoma (PDS). As this concept is not universally accepted, we aim to further characterize their clinical and morphological features as well as behavior.
Design: 32 PDS were retrieved from the departmental files at NHS Lothian, Edinburgh, UK. Hematoxylin and eosin-stained tissue sections as well as immunohistochemistry for multiple markers were assessed to exclude epithelial, melanocytic, smooth muscle and endothelial differentiation. Clinical and follow-up data were obtained.
Results: Median age at presentation was 81 years (range: 47-96) with a strong male predilection. All tumors occurred on sun-damaged skin, mostly of the scalp. Only one tumor was located outside the head and neck area.
Tumors were nodular or polypoid with median thickness of 11.5mm (range: 3.5-26). When available for assessment, all tumors invaded at least into deep subcutis. Skeletal muscle or fascia involvement was identified in 82%, and ulceration in 78% of cases. The tumors were composed of fascicles of atypical spindle cells, or less frequently of sheets of pleomorphic epithelioid cells. A subset of tumors showed mixed features and multinucleated tumor giant cells were admixed in varying proportions. Additional findings were myxoid, desmoplastic, pseudoangiomatous, keloidal or storiform growth patterns. The mitotic count was brisk, including atypical forms, and tumor necrosis was observed in 22%. Lymphovascular invasion was noted in 5, perineurial infiltration in 7 patients.
Multiple cytokeratin markers, S100, HMB-45, desmin and CD34 were negative. SMA was expressed in 70% of cases, EMA in 16%, CD31 in 48%, Melan A in 6% and p63 in 1 case only.
Follow-up (median, 20 months) was available for 28 patients. 6 patients recurred locally with no further recurrences in 4 patients. 1 patient developed further recurrences as well as multiple cutaneous metastases, and died after 13 months. 5 patients died from unrelated and 5 from unknown cases.
Conclusions: This study outlines the clinical and morphological features of PDS. Tumors may recur locally but distant metastasis and disease related death is rare despite the deep invasion and presence of lymphovascular invasion.
Category: Dermatopathology

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 89, Tuesday Morning

 

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