An 88-year-old male patient was referred to the Department of Dermatology with an exophytic, bleeding nodule on the scalp. His medical history was positive for cutaneous squamous cell carcinoma with field cancerization on the scalp, diabetes mellitus type 2, renal insufficiency, atrioventricular block with pacemaker implantation, hypertension, hypothyreosis, gonarthrosis, and partial pulmonary resection during World War II.

On physical examination we observed a firm large scalp tumor with bleeding (Fig. 41.1). We performed a wide complete excision with 2 cm safety margins. The defect was closed with a meshed skin graft. Healing was uneventful (Fig. 41.2). A histological examination demonstrated a connective tissue derived tumor with spindle cells (Fig. 41.3). The tumor thickness was 18 mm. The spindle shaped lesion demonstrated nuclear polymorphism and atypia. The tumor cells expressed vimentin, CD68, and partially smooth-muscle actin. Numerous mitoses including typical were seen. The tumor was well vascularized. There was no relapse during 24 months of follow-up.

Fig. 41.1
figure 1

A bleeding, exophytic nodule surrounded by field cancerization on the scalp

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Fig. 41.2
figure 2

A surgical excision of the nodule on the scalp. (a) Defect after wide excision. (b) Meshed graft transplantation. (c) Seven days after surgery, stable transplant with 100% take rate

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Based on the case description and the photographs, what is your diagnosis?

FormalPara Differential Diagnoses
  1. 1.

    Merkel cell carcinoma.

  2. 2.

    Basal cell carcinoma.

  3. 3.

    Atypical fibroxanthoma.

  4. 4.

    Pleomorphic dermal sarcoma.

  5. 5.

    Squamous cell carcinoma.

FormalPara Diagnosis

Atypical fibroxanthoma.

Discussion

The presented patient had been treated for years by dermatologists due to his field cancerization the scalp. Most lesions were classified as actinic keratoses or carcinoma in situ. Two years ago, the first squamous cell carcinoma was surgically removed. Therefore, the primary suspicion in the patient was squamous cell carcinoma [1].

However, histology showed a connective tissue tumor with the presence of spindle cells (Fig. 41.3). The tumor thickness was 18 mm. Spindle cells demonstrated both, cell and nuclear, polymorphism. The tumor cells expressed vimentin, CD68, and partially smooth-muscle actin. Numerous mitoses were seen. The tumor was well-vascularized. Based on the histology, the diagnosis of atypical fibroxanthoma was established.

Fig. 41.3
figure 3

Histology of atypical fibroxanthoma. (a) Dermal tumor without infiltration of the subcutaneous tissue (hematoxylin-eosin, ×2). (b) Immuno-peroxidase stain for CD68 (×20)

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Atypical fibroxanthoma is a rare mesenchymal neoplasia characterized by a rapid and exophytic growth with frequent ulceration of the overlying epidermis. The mean age of patients with atypical fibroxanthoma is about 80 years. The tumor typically occurs on the sun-exposed body areas. Men are more often affected than women. Histologically, atypical fibroxanthoma is well-circumscribed, dermal-based neoplasm composed of a variable amount of large histiocytoid cells, enlarged spindled and epithelioid cells, and multinucleated giant cells [2, 3].

Treatment of choice for atypical fibroxanthoma is complete surgical excision with a safety margins of 2 cm. Alternatively, Mohs surgery can be used [4].

Key Points

  • Atypical fibroxanthoma is a rare mesenchymal tumor of the elderly.

  • It is usually localized on the head and neck areas.

  • Rapid growth and ulceration/bleeding are commonly presented, however clinical features of atypical fibroxanthoma are non-specific.

  • Treatment of choice is complete surgical excision.

  • Patient with atypical fibroxanthoma often develop other skin cancers thus follow-up is recommended.