Recurrent atypical fibroxanthoma with satellite metastasis

Keloidal atypical fibroxanthoma of the scalp

Atypical fibroxanthoma (AFX) is a rare low-grade sarcoma that occurs mainly in the elderly and may recur locally. There are multiple variants including keloidal AFX (KAF). KAF is characterised by a proliferation of atypical spindled and epithelioid cells admixed with bizarre pleomorphic cells. These cells intersect among broad bands of keloidal collagen. AFX is a diagnosis of exclusion so a broad panel of immunohistochemical staining should be applied to rule out other differentials (squamous cell carcinoma (SCC), melanoma, leiomyosarcoma, etc). There is added difficulty with the diagnosis of KAF as it may mimic multiple keloidal lesions, including exuberant scarring, as in this case. p53 immunohistochemistry staining can be useful in highlighting the presence of tumour cells. Additionally, next generation sequencing can detect genetic mutations identified in clonal proliferations consistent with tumour formation. KAF is easily overlooked and it should be included in the differential diagnosis for keloidal lesions showing even mild atypia.

Surgical excision margins for fibrohistiocytic tumors, including atypical fibroxanthoma and undifferentiated pleomorphic sarcoma: A probability model based on a systematic review

BACKGROUND

Mohs micrographic surgery or wide local excision is the treatment of choice for fibrohistiocytic tumors with metastatic potential, including atypical fibroxanthoma (AFX) and cutaneous undifferentiated pleomorphic sarcoma (cUPS). Since margin clearance is the strongest predictor of clinical recurrence, improved recommendations for appropriate surgical margins help delineate uniform excision margins when intraoperative margin assessment is not available.

OBJECTIVE

To determine appropriate surgical wide local excision margins for AFX and cUPS.

METHODS

Literature search (Ovid MEDLINE, Embase, Web of Science, and Cochrane Library from inception to March 2020) to detect case-level data. Estimation of margins required using a mathematical model based on extracted cases without recurrences.

RESULTS

Probabilistic modeling based on 100 cases extracted from 37 studies showed peripheral clearance margin (ie, wide local excision margin) calculated to clear 95% of all tumors was 2 cm for AFX and 3 cm for cUPS. AFX tumors 1 cm or less required a margin of 1 cm.

LIMITATIONS

Data were extracted from published cases.

CONCLUSIONS

Atypical fibroxanthoma removed with at least a 2-cm peripheral excision margin is less likely to recur. Smaller tumors 1 cm or less can be treated with a more conservative margin. Margin-control surgical techniques are recommended to ensure complete removal while minimizing surgical morbidity.

Atypical fibroxanthoma and pleomorphic dermal sarcoma: A reappraisal

BACKGROUND

Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) share clinical, pathological, immunohistochemical and molecular features, though PDS is associated with a more aggressive behavior.

METHODS

We reviewed 71 tumors fulfilling criteria for AFX and PDS to further stratify their biological potential.

RESULTS

Lesions were mainly located on the scalps of elderly men, and were often ulcerated. One case was necrotic, one showed vascular invasion, and one showed perineural invasion. Fifty-one tumors were limited to reticular dermis (71.8%), 20 invaded subcutaneous tissue, focally in 13 cases (18.3%), and diffusely in seven (9.9%). Subcutaneous invasion was present significantly more often in tumors showing predominantly spindle compared to pleomorphic/mixed cell morphology (P = 0.02). At a follow-up of 17-125 months, 4 cases recurred locally, 4, 6, 10 and 13 months after surgery; no metastases were observed. Three tumors were composed of spindle cells, and one of clear cells. Three cases had margins focally involved, while the fourth case had clear margins.

CONCLUSION

Depth of invasion and state of margins are criteria predicting prognosis in AFX/PDS; in addition, spindle cell morphology seems to be related to a more infiltrative pattern of growth and to aggressiveness. Grouping these tumors on a morphologic base could help to clarify their different biological behavior.

Incidence and Clinical Features of Rare Cutaneous Malignancies in Olmsted County, Minnesota, 2000 to 2010

BACKGROUND

The incidence of rare cutaneous malignancies is unknown. Current estimates of rare cutaneous malignancy incidences are based on broad epidemiologic data or single institution experiences, not population-based data.

OBJECTIVE

To determine the incidence of several rare nonmelanoma skin cancers.

MATERIALS AND METHODS

The authors conducted a retrospective chart review of a population-based cohort between the years 2000 and 2010. Residents of Olmsted County, Minnesota, who were diagnosed with a biopsy-proven nonmelanoma skin cancer-excluding basal cell carcinoma and squamous cell carcinoma-were included in this study. The primary outcome was tumor incidence. Additionally, the authors extracted patient demographics, tumor characteristics, treatment modalities, and outcomes.

RESULTS

The age-adjusted and sex-adjusted incidences per 100,000 persons of multiple rare cutaneous malignancies were: atypical fibroxanthoma (1.8), sebaceous carcinoma (0.8), dermatofibrosarcoma protuberans (0.4), microcystic adnexal carcinoma (0.7), eccrine carcinoma (0.4), eccrine porocarcinoma (0.2), and leiomyosarcoma (0.2).

CONCLUSION

The authors report population-based incidences and clinical characteristics for these rare cutaneous malignancies. The immune status and smoking status of patients and the treatment and outcomes of these tumors are reported. Additional studies in a broader population are needed to further define the epidemiology and outcomes of these malignancies.

The utility of positron emission tomography with and without computed tomography in patients with nonmelanoma skin cancer

Combined positron emission tomography (PET) and computed tomography (CT) scans are widely used in the staging and monitoring of most malignancies. The differential for PET-positive cutaneous lesions includes primary skin cancers, infections, cutaneous metastases from distant malignancies, and benign neoplasms. In dermatology, PET/CT scans have been most widely studied in patients with melanoma and Merkel cell carcinoma. The role of PET/CT scans in the management of other cutaneous malignancies is less clear, but it has shown great promise in the management of patients with squamous cell carcinoma and cutaneous lymphoma. This review seeks to address the usefulness of PET/CT scans in nonmelanoma skin cancer and to provide guidance regarding the management of patients with incidental PET-positive nodules. Currently, there is limited experience with PET/CT scans for staging and monitoring of non-head and neck metastatic basal cell and squamous cell carcinomas, and results show limited sensitivity and specificity. We also address the evidence for management of an incidental PET-positive cutaneous nodule and recommend obtaining a biopsy specimen in patients with a known noncutaneous malignancy, a history of primary skin cancer, or a high risk of either cutaneous or noncutaneous malignancy.

Pleomorphic dermal sarcoma: a more aggressive neoplasm than previously estimated

BACKGROUND

Pleomorphic dermal sarcoma (PDS) is a rare neoplasm sharing pathological features with atypical fibroxanthoma, but adding tumor necrosis, invasion beyond superficial subcutis or vascular or perineural infiltration. Although its metastatic risk has been estimated to be less than 5%, its real outcome is presently uncertain because of its rarity and to the lack of homogeneous criteria used in reported cases.

METHODS

Retrospective clinicopathological study of 18 cases of PDS.

RESULTS

The lesions presented as tumors or plaques (size: 7-70 mm) on the head of elderly patients (median: 81 years), without a gender predominance. Histopathologically, they consisted of spindle cells arranged in a fascicular pattern, containing pleomorphic epithelioid and giant multinucleated cells in varying proportions, and usually exhibiting numerous mitotic figures and infiltrative tumor margins. No immunoexpression for cytokeratins, S100 protein, desmin or CD34 was observed. Necrosis and venous invasion were found in three tumors each (17%). Follow-up was available in 15 cases (median: 33 months). Three patients (20%) had local recurrences, all with incomplete primary surgical resections. Three patients (20%) developed distant metastases in the skin, regional lymph nodes and/or lungs and died from the disease.

CONCLUSION

Our data suggest that PDS may be a more aggressive neoplasm than previously estimated.