Peritoneal metastases from an atypical fibroxanthoma

Conception and Management of a Poorly Understood Spectrum of Dermatologic Neoplasms: Atypical Fibroxanthoma, Pleomorphic Dermal Sarcoma, and Undifferentiated Pleomorphic Sarcoma

OPINION STATEMENT

Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) tumors share many clinical, etiologic, and histologic features and likely represent components of a tumor spectrum. In dermatologic oncology, differentiating between AFX and PDS is pivotal as tumors with histological features consistent with PDS are more likely to behave in a clinically aggressive manner. Importantly, the term "pleomorphic dermal sarcoma" (PDS) is a more appropriate designation than "undifferentiated pleomorphic sarcoma" (UPS) for describing deeper, more aggressive, histologically high-grade cutaneous tumors that otherwise resemble AFX. Surgery remains the gold standard for treatment. In the setting of AFX, excision with the Mohs micrographic technique appears to offer superior tumor control rates while maintaining greater tissue preservation over wide local excision and should be considered first line. In the setting of PDS, optimal management is less clear given the paucity of available data. However, due to its greater propensity to recur and metastasize, extirpation with complete tumor margin control appears paramount. The roles of imaging and SLNB in management and clinical outcomes of AFX and PDS are unclear given the lack of available data. In reality, these tools are unlikely to be helpful in most cases of AFX. However, in the setting of PDS, emerging literature indicates that these tumors are inherently higher risk, and thus, imaging and SLNB may be helpful in select cases. Additionally, radiation therapy may be of adjuvant benefit for these tumors when clear surgical margins cannot be obtained. While traditional chemotherapy has been largely ineffectual, the recent discovery of key oncogenetic mutations has allowed for the identification of several potential molecular drug targets that may have a therapeutic role with future study. In the unfortunate setting of metastatic disease, a multidisciplinary approach is optimal. Further studies are needed to establish definitive conclusions regarding risk stratification and best management practices.

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.

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.

Molecular pathology of skin neoplasms of the head and neck

CONTEXT

Skin neoplasms include the most common malignancies affecting humans. Many show an ultraviolet (UV)-induced pathogenesis and often affect the head and neck region.

OBJECTIVE

To review literature on cutaneous neoplasms that show a predilection for the head and neck region and that are associated with molecular alterations.

DATA SOURCES

Literature review.

CONCLUSIONS

Common nonmelanoma skin cancers, such as basal and squamous cell carcinomas, show a UV-induced pathogenesis. Basal cell carcinomas are characterized by molecular alterations of the Hedgehog pathway, affecting patched and smoothened genes. While squamous cell carcinomas show UV-induced mutations in several genes, driver mutations are only beginning to be identified. In addition, certain adnexal neoplasms also predominantly affect the head and neck region and show interesting, recently discovered molecular abnormalities, or are associated with hereditary conditions whose molecular genetic pathogenesis is well understood. Furthermore, recent advances have led to an increased understanding of the molecular pathogenesis of melanoma. Certain melanoma subtypes, such as lentigo maligna melanoma and desmoplastic melanoma, which are more often seen on the chronically sun-damaged skin of the head and neck, show differences in their molecular signature when compared to the other more common subtypes, such as superficial spreading melanoma, which are more prone to occur at sites with acute intermittent sun damage. In summary, molecular alterations in cutaneous neoplasms of the head and neck are often related to UV exposure. Their molecular footprint often reflects the histologic tumor type, and familiarity with these changes will be increasingly necessary for diagnostic and therapeutic considerations.

Sarcoma-like tumor of head and neck skin

A group of tumors referred to as atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) predominantly occur in sun-damaged skin of the elderly, particularly in the head and neck region. Although this group of tumors is often regarded as of mesenchymal phenotype, the matter of histogenesis has not been entirely resolved. Evans H and Smith JL reported in 1980 that prognosis was not significantly different irrespective of whether there was a definite squamous cell carcinoma component or not, supporting a view that these are all carcinomata in nature (sarcomatoid carcinoma [SC]). There are a number of clinicopathologic studies of AFX in the literature but information on morphologically similar sarcoma-like tumors with immunohistochemical evidence of epithelial differentiation is sparse. One hundred sarcoma-like tumors (SLTs) of head and neck skin of the elderly, treated by surgical excision, were studied. Clinical information was obtained, and pathology reports and hematoxylin and eosin sections were reviewed to document size (maximum dimension), extent of invasion, mitotic count, vascular and perineural invasion, margin status, ulceration, necrosis, and the presence of actinic keratosis in adjacent/overlying skin. Immunostains examined included: pan-cytokeratins (CKs) (AE1/AE3, MNF116), high-molecular weight CKs (34βE12, CK5/6, CK14), p63, and melanocytic (S100, Melan A, HMB-45, MITF), vascular (CD31, CD34), and muscle markers (SMA, desmin, h-caldesmon) to exclude melanoma and definite sarcoma entities. The tumors were divided into AFX/PDS (G1), the SC group, which was subdivided into SLT with only p63 positivity (G2a) and SLT with CK positivity regardless of p63 status (G2b), and SLT with a minor morphologic squamous cell carcinoma component (G3). Clinicopathologic findings of each group were compared, in relation to outcomes. Age at diagnosis ranged from 51 to 96 years (median, 79 y), with M:F=11.5:1. There were 53 tumors in G1 (19AFX, 34PDS), 37 in G2 (25 in G2a, 12 in G2b), and 10 in G3. There was no statistically significant difference in clinical and pathologic parameters or survival among all 3 groups. CKs and p63 expression, size, extent of invasion, vascular invasion, perineural invasion, mitotic count, and ulcer did not affect outcome, whereas margin status and necrosis did by both univariate and multivariate analysis and by only univariate analysis, respectively. Sixty patients had multiple nonmelanomatous skin cancers. Actinic keratosis was observed in overlying/adjacent epidermis in 51 cases. Eight patients had prior radiotherapy to head skin cancers; 1 patient developed 2 separate tumors (G1 and G3) after radiotherapy. Four patients died of tumor (1 G1, 2 G2b, and 1 G3); of these, 3 cases had positive margin, and 1 had narrow margin. Our results have shown similarities of various clinicopathologic parameters between AFX/PDS and SC, raising the possibility that both entities are related, and some of the former entities may represent complete dedifferentiation (complete loss of epithelial phenotype) with a gain of mesenchymal phenotype. In addition, the difference between AFX and PDS appears to be the extent of invasiveness (stage) rather than a different histogenesis. Further investigations are needed. However, from a practical point of view, efforts should be made to excise this group of tumors with clear margins, as margin status appears to be the most important prognostic factor regardless of the presence or absence of epithelial differentiation.

Atypical fibroxanthoma: new insights

Atypical fibroxanthoma (AFX) is an ultraviolet radiation-associated dermal neoplasm. To address the clinicopathologic and molecular features of this particular neoplasm. The author conducted a literature review using PubMed searching for articles relating to AFX. AFX usually appears as a rapidly growing nodular or nodulo-ulcerative lesion. It occurs on sun-exposed skin of elderly peoples. AFX may be composed predominantly of pleomorphic, spindle, epithelioid cells, or admixture of these cells. The differential diagnosis of AFX includes pleomorphic dermal sarcoma, squamous cell carcinoma, malignant melanoma and leiomyosarcoma. Several observations favor a mesenchymal origin for AFX. These reviews address the clinicopathologic features, molecular pathology, prognosis and treatment of this neoplasm.

Pleomorphic dermal neoplasms: a review

Pleomorphic neoplasms are typically associated with high-grade malignant behavior, but this does not readily apply to primary cutaneous tumors. Despite morphologic features suggestive of malignancy, atypical fibroxanthoma, the classic example of a pleomorphic dermal neoplasm, is characterized by indolent clinical behavior. Atypical fibroxanthoma is a distinctive clinicopathologic disease affecting sun-damaged skin of elderly males. Histologically, it is often ulcerated and dermal based with pushing growth, characterized by a sheet-like and fascicular growth of pleomorphic epithelioid, spindled, and multinucleated tumor cells with brisk and atypical mitotic activity. However, no positive discriminatory histologic or immunohistochemical features exist. Its diagnosis is one exclusion with a wide differential diagnosis, mainly including other mesenchymal, melanocytic, and epithelial neoplasms. Particular considerations are pleomorphic dermal sarcoma, invasive melanoma, squamous cell carcinoma, metaplastic carcinoma, poorly differentiated cutaneous angiosarcoma, cutaneous leiomyosarcoma, myxofibrosarcoma, variants of fibrous histiocytoma (FH), pleomorphic fibroma, and non-neural granular cell tumor. The behavior of these tumors is varied and ranges from outright malignant to entirely benign, requiring confident diagnosis to reliably predict behavior and guide treatment. Although challenging, because of significant clinical and pathologic overlap, it is usually possible to establish a definitive diagnosis when attention is paid to the often subtle differentiating features. This requires careful tumor sampling, recognition of the subtle distinguishing morphologic features, judicious use and analysis of immunohistochemistry, and interpretation of the findings in the appropriate clinical setting.

Optimising the management of soft tissue tumours

The Royal College of Pathologists of Australasia is developing a series of protocols as an educational tool to assist pathologists in the reporting of relevant information for specific cancer specimens. The protocol for the management of soft tissue tumour resections has recently been released, and this document elaborates the relevant literature on which that protocol drew. Sarcoma is uncommon but is associated with significant morbidity and mortality, and its management is complex. Diagnostic errors are not uncommon and these can have disastrous effects on patient outcome. Sophisticated ancillary testing is often an important adjunct to diagnosis and prognostication. Referral to a specialist sarcoma unit is indicated for both adult and paediatric sarcoma.

Cutaneous fibrohistiocytic tumours - an update

The term 'fibrohistiocytic' tumour is a descriptive designation without histogenetic connotation for a group of heterogeneous lesions that share morphological features of histiocytes and fibroblasts on light microscopy. However, over the years it has become apparent that many so-called 'fibrohistiocytic' tumours are largely composed of relatively undifferentiated mesenchymal cells, but can also show areas of myofibroblastic differentiation. This review focuses on the clinical and histological features as well as differential diagnosis of so-called fibrohistiocytic tumours. Special emphasis is given to more recently described histological variants of fibrous histiocytoma, e.g. cellular, epithelioid, aneurysmal and atypical fibrous histiocytoma, to angiomatous and plexiform fibrous histocytoma (plexiform fibrohistiocytic tumour), lesions that are not true variants of fibrous histiocytomas but have erroneously been designated such, and to atypical fibroxanthoma. The literature on metastasizing fibrous histiocytoma is also reviewed.

CD10, p63 and CD99 expression in the differential diagnosis of atypical fibroxanthoma, spindle cell squamous cell carcinoma and desmoplastic melanoma

BACKGROUND

Atypical fibroxanthoma (AFX) is a pleomorphic spindle cell lesion of the skin; it is considered in the differential diagnosis with spindle cell malignant melanoma (MM) and sarcomatoid carcinoma/spindle cell squamous cell carcinoma (SCC). An optimum approach has yet to fully emerge with respect to the immunohistochemical discrimination of these lesions.

METHODS

Departmental archives from 1978 onwards were searched for clinicopathologically confirmed cases of AFX, MM and SCC. Immunostains for CD10, CD99 and p63 were performed in each case. Scored staining results were analyzed using Fisher's Exact Test.

RESULTS

Twenty-seven of 31 cases of AFX were positive for CD10, as compared with 3 of 22 SCCs and 0 of 20 MMs. CD10 positivity was preferentially associated with the diagnosis of AFX (p < 0.001). p63 reactivity was observed in 15/22 cases of SCCs, 5/31 AFXs and 1/20 MMs. CD99 reactivity was observed in 3/31 cases of AFX, 2/22 SCCs and 3/20 MMs.

CONCLUSION

CD10 positivity is relatively specific in this context for the diagnosis of AFX. Its utility is enhanced when only strong, diffuse membranocytoplasmic staining is considered as a positive result. In contrast to prior reports, p63 was not found to be highly sensitive for SCC. Similarly, CD99 showed no preferential staining of any single diagnostic group of lesions.

Atypical fibroxanthoma: a series of 25 cases

OBJECTIVE

Atypical fibroxanthoma is a rare mesenchymal tumour of skin that develops on skin of elderly patients. We analysed our patients with atypical fibroxanthoma over the last 8 years.

PATIENTS AND METHODS

We analysed the pathology files of our hospital for the period 2001-2009. In all cases, histology and immunohistology were performed. Data on co-morbidities, treatment and outcome were obtained.

RESULTS

We identified 25 patients (except two female patients, the rest were men) aged 52-95 years (mean: 79.5 years; standard deviation +/- 9.06 years). All tumours were localized in the head and neck region, except a single tumour on the shoulder. Fourteen patients had a cancer history, six had actinic keratoses or Bowen's disease (n = 1). Five patients had cardiac surgery or pacemaker, one each had a renal transplant, systemic sarcoidosis or non-Hodgkin's lymphoma. Medical history was positive for radiotherapy or chemotherapy in four patients. Histology showed a spindle-shaped dermal and subcutaneous tumour growth intermingled with multinucleated giant cells. The phenotype of tumour cells was vimentin-positive, but S100- and keratin-negative. Some tumours showed a focal expression of CD68. Complete microhistographic controlled surgery ('Mohs like') was possible in all cases followed by mesh-graft transplantation in three patients. Eighteen patients showed a complete remission. Four patients had a relapse within 2 years of follow-up treated by surgery. One patient is still under radiotherapy. All patients with a safety margin of 2 cm had no recurrence or relapse during follow-up.

CONCLUSIONS

Micrographic controlled surgery with wide 2 cm safety margins is the treatment of choice. A regular follow-up for the next 5 years is recommended.

Keloidal atypical fibroxanthoma: a case series

BACKGROUND

Keloidal atypical fibroxanthoma (AFX) is a rare variant of AFX with thick bands of hyalinized collagen. The identification of keloidal collagen associated with fibrohistiocytic cells may erroneously lead to the diagnosis of keloidal dermatofibroma. Although AFX is a pleomorphic cutaneous tumor typically associated with a good prognosis, occasional reports of metastatic AFX highlight the importance of accurate identification.

METHODS

A total of nine cases of an unusual variant of AFX with keloidal tumoral sclerosis were collected and examined. The cases were stained with antibodies directed against S100, cytokeratin, CD68 and CD31.

RESULTS

Histopathological examination revealed pleomorphic cells trapped within hyalinized keloidal collagen bands. In several cases, the keloidal collagen also formed ring-shaped structures surrounding CD31-positive vascular structures. Pleomorphic cells were negative for S100 protein and keratin, but consistently labeled with antibodies directed against CD68.

CONCLUSIONS

The diagnosis of keloidal AFX requires the exclusion of other malignant and benign lesions with keloidal or sclerotic collagen. Awareness of the rare variant of keloidal AFX may avoid a diagnostic pitfall leading to an erroneous diagnosis, particularly in small biopsies. The finding of sclerotic collagen preferentially deposited around vessels is an interesting and poorly understood phenomenon.

Evaluation of CD10 and procollagen 1 expression in atypical fibroxanthoma and dermatofibroma

Atypical fibroxanthoma (AFX) (dermal pleomorphic sarcoma) remains a somewhat controversial entity. Some authors have averred that AFX is a fiction, suggesting that such lesions merely represent misclassified examples of spindled squamous cell carcinoma. In addition, the immunoperoxidase confirmation of AFX has been less than straightforward and has historically been approached as a diagnosis of exclusion because of the lack of sensitivity and specificity of available "positive" reagents. Procollagen 1 (PC1) and CD10 represent recently developed immunoperoxidase reagents that have been forwarded as useful in this setting, and we sought to characterize our experience, both to confirm the utility of these antibodies and to compare them. Our investigation included 3 separate data sets. Group 1 consisted of a retrospective review of 98 consecutive cases in which PC1 was used in the evaluation of dermatopathology specimens in routine practice during a 13-month interval. Group 2 consisted of a direct comparison of 11 AFX, 11 dermatofibroma (DF), and 7 epithelioid dermatofibroma (EDF) using the CD10 reagent on cases identified by database search. Group 3 consisted of a retrospective review of 47 cases in which CD10 was used in routine practice during a 10-month interval. Group 1 included 47 AFX, 13 carcinomas, and 6 melanomas. PC1 expression was observed in 45 of 47 AFX (96%), with a strong reaction in 78% of cases. Among a comparison group of carcinomas, 13 of 13 displayed strong keratin immunopositivity and 11 of 13 (85%) lacked PC1 expression whereas 2 showed focal weak labeling. Six of six melanomas exhibited avid S100 expression and none labeled with PC1. In group 2, strong CD10 immunoreactivity was present in 11 of 11 AFX. Similarly, 11 of 11 DFs were also positive. In contrast, 6 of 7 cases of EDF lacked CD10 expression. Group 3 included 38 AFX and 9 miscellaneous spindle cell proliferations. Of the 38 AFX, 37 (97%) labeled with CD10 and in 34 (92%) the reaction was strong. PC1 immunostaining was also completed in 34 of 38 AFX from group 3 and 27 (79%) cases showed positive labeling. Our results confirm that both PC1 and CD10 can be used as positive markers of AFX. We believe that CD10 and PC1 immunostaining can be used as a useful adjunct to supplement the diagnosis of AFX, within the context of an immunoperoxidase panel. Not surprisingly, CD10 expression is also common in DF, a benign analog of AFX, with the exception of its epithelioid variant. In direct head-to-head comparison, our experience indicates that the staining of AFX with CD10 is more avid than that observed with PC1. Lastly, out data includes over 80 examples of AFX, <5% of which showed keratin labeling. Given a general lack of keratin expression, it seems unlikely that AFX merely represents poorly differentiated squamous carcinoma.

More than 2 decades of treating atypical fibroxanthoma at mayo clinic: what have we learned from 91 patients?

BACKGROUND

Atypical fibroxanthoma (AFX) typically occurs on the head and neck of elderly white men. Usually considered a malignancy, it is treated with wide local excision (WLE) or total margin control using Mohs micrographic surgery (MMS).

OBJECTIVE

To determine the most appropriate treatment for this tumor based on a review of cases treated at Mayo Clinic.

METHODS

We reviewed the medical records of patients with AFX treated at Mayo Clinic from 1980 to 2004.

RESULTS

We identified 91 patients with 93 tumors. Treatment information was available for 88 tumors (59 treated with MMS, 23 with WLE, and 6 by other means). There were no recurrences in the patients treated with MMS, with a median follow-up of 4.5 years (range 1.0-16.1 years). Two patients treated with WLE had single recurrences, with a median follow-up of 8.7 years (range 1.5-26.3 years).

CONCLUSIONS

Total microscopic margin control using MMS was the most effective means of treating AFX.