Clear cell atypical fibroxanthoma:a clinicopathologic study

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.

Clear cell variant of atypical fibroxanthoma and pleomorphic dermal sarcoma: molecular characterization and review of the literature

Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) are unusual cutaneous tumors that typically arise in sun-damaged skin of elderly individuals. Several histopathologic variants have been described, but the clear cell variant is particularly rare with only 18 cases of AFX and 1 case of PDS reported. Here, we present two cases of clear cell AFX and PDS highlighting key histopathologic findings and molecular alterations assessed by next generation sequencing (NGS).

Atypical Fibroxanthoma Revisited

Atypical fibroxanthoma (AFX) represents a rare mesenchymal neoplasm arising predominantly in the head and neck area of elderly patients. Clinically, the neoplasm is characterized by a rapid and exophytic growth with frequent ulceration of the epidermis. Histopathologically, AFX represents a well-circumscribed, dermal-based neoplasm composed of a variable admixture of large histiocytoid cells, enlarged spindled and epithelioid tumor cells, and multinucleated tumor giant cells with bizarre and pleomorphic nuclei. If strict diagnostic criteria are applied, the clinical behavior of AFX is benign in most cases, and complete excision represents the treatment of choice.

Primary dermal pleomorphic liposarcoma: utility of adipophilin and MDM2/CDK4 immunostainings

Liposarcoma, usually arises in deep soft tissues and pleomorphic liposarcoma (PL), is the rarest histopathologic variant. However, 15 cases of entirely dermal PL have been reported. We describe a case of a 79-year-old man who developed a rapidly growing nodule on his thorax. Excisional biopsy was performed and immunohistochemical studies were carried. The lesion was a well-circumscribed dermal nodule composed of multivacuolated pleomorphic lipoblasts and atypical mitotic figures. Neoplastic cells expressed CD10 and resulted negative S100 protein, Melan-A, MITF-1, AE1/AE3, CD4, CD68 (PGM1), retinoblastoma gene family protein, pericentrine and lysozyme. Adipophilin stain showed the lipid contents in the cytoplasm of the neoplastic cells. MDM2 and CDK4 resulted both negative. A diagnosis of primary dermal PL was made. This case shows the utility of adipophilin immunostaining to prove the lipid contents in neoplastic cells, which has the advantage of using formalin-fixed paraffin-embedded tissue and making needless frozen sections and ultrastructural studies to show these findings. Negative MDM2/CDK4 staining in our case argues against the possibility of dedifferentiated liposarcoma and further supports the diagnosis of true PL.

Clear-Cell Atypical Fibroxanthoma: A Combined Immunohistochemistry Analysis

Atypical fibroxanthoma is considered to be a low-grade sarcoma, characterized by a proliferation of bizarre spindled cells. A case of a rare variant of this tumor, a clear-cell atypical fibroxanthoma, presenting with rapid growth on a 63-year-old female, is reported. The differential diagnosis of a clear cell proliferation and a review of the immunohistochemistry markers used in the diagnosis of atypical fibroxanthoma are discussed. In particular, the usefulness of markers such as CD10, procollagen 1, CD68, CD163, CD99, and S100A6, and the importance of negative markers such as S100, cytokeratin, and desmin are emphasized. Furthermore, the development of a keratoacanthoma at the site of previous Mohs surgery is recounted.

Clear cell proliferations of the skin

Clear cell proliferations of the skin consist of a diverse group of lesions characterized by the presence of cells with abundant clear cytoplasm. They may arise from primary, metastatic, or non-neoplastic origins, with their distinctive cytoplasmic clearing attributable to causes ranging from artifact to accumulation of materials such as glycogen, mucin, or lipids. Despite the heterogeneity of these lesions, their distinguishing characteristics may be subtle, especially at high power. As such, histologic diagnosis can be challenging, and proper consideration relies on an understanding of the scope of possible origins, etiologies, and key immunohistochemical staining patterns of the various entities. This review categorizes cutaneous clear cell neoplasms by histogenesis, and offers differential diagnostic strategies to aid in their clinicopathologic evaluation.

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.

Clear cell atypical fibroxantoma: a rare variant of atypical fibroxanthoma and review of the literature

Atypical fibroxanthoma (AFX) is a superficial variant of pleomorphic malignant fibrous histiocytoma. Clear cell atypical fibroxanthoma (CCAFXA) is a rare variant of atypical fibroxanthoma. A 74-year-old male patient presented with a rapidly growing nodule on the shoulder, which had appeared over a 5-months period. Lesion was excised by the plastic surgeon. Microscopic examination showed an ulcerated nodule composed of pleomorphic spindled and polygonal cells with clear or vacuolated cytoplasm. The neoplastic cells were stained positively with CD68 and CD10 and were stained negative with S-100, Melan A, muscle-specific actin, or pan-cytokeratin. Final diagnosis was clear cell atypical fibroxanthoma. CCAFXA should be differentiated from other clear-cell neoplasms of the skin. Best of our knowledge only 11 cases CCAFXA of have been reported in published studies till date. Herein, we reported 12th case in literature of CCAFXA and review of the literature.

Clear Cell Tumors of Soft Tissue

Clear cell lesions of soft tissue include varying morphologic patterns and a range of clinical behaviors and prognoses. Benign lesions include perivascular epithelioid cell tumors, clear cell fibrous papule, and distinctive dermal clear cell mesenchymal tumor; malignant tumors include clear cell sarcoma, liposarcoma, and rare malignant perivascular epithelioid cell tumors. Clear cell variants of other benign and malignant soft tissue tumors include fibrous histiocytoma, atypical fibroxanthoma, myoepithelioma, leiomyoma and leiomyosarcoma, and rhabdomyosarcoma. Metastatic clear cell tumors, including renal cell carcinoma and adrenal cortical carcinoma, should be considered in the differential diagnosis and excluded through clinical history, imaging studies, and immunohistochemical stains.

Granular cell atypical fibroxanthoma: case report and review of the literature

We present a case of granular cell atypical fibroxanthoma of the scalp. The neoplasm occurred as a tender nodule on the frontal scalp of an 82-year-old Caucasian man. Histology demonstrated a diffuse proliferation of atypical epithelioid cells with abundant granular cytoplasm. Many of the cells had large irregular nuclei and atypical mitotic figures were present. Immunohistochemical stains were positive for CD68 and procollagen 1 and negative for cytokeratin, HMB-45 and S-100 protein. The granular cell phenotype has been observed in other cutaneous neoplasms including granular cell tumors, dermatofibromas, dermatofibrosarcoma protuberans, fibrous papules, basal cell carcinomas, leiomyosarcomas, angiosarcomas and primitive polypoid granular cell tumors. We discuss the differential diagnosis and review the previously reported cases of this rare variant of atypical fibroxanthoma.

Combined Papillated Bowen Disease and Clear Cell Atypical Fibroxanthoma

We describe a case of papillated Bowen disease (PBD), associated with a clear cell atypical fibroxanthoma (CCAFXA). The epidermal lesion showed a bowenoid papillomatous growth pattern with histologic features suggestive of infection by human papilloma virus (HPV). In the dermis a neoplasm made up by spindled or polygonal cells with wide clear cytoplasm and moderate nuclear pleomorphism was found. Immunohistochemical characteristics of these two lesions were clearly different. The atypical cells of the intraepidermal proliferation were positive for AE1-AE3 anticytokeratin antibody, EMA, p16, p53 and p63. The dermal tumor was positive for vimentin, CD10, CD68, CD99, alpha-1-antitrypsin and c-kit. Histological features and immunohistochemical profile of the dermal tumor corresponded to a CCAFXA, a very uncommon neoplasm of which only 10 cases have been reported. In situ hybridization for numerous types of HPVs was negative in both lesions.

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.

Morphological and immunohistochemical characteristics of atypical fibroxanthoma with a special emphasis on potential diagnostic pitfalls: a review

The present manuscript gives emphasis on recognizing different morphological variants of atypical fibroxanthoma (AFX), on validation of immunohistochemical markers and on discussing potential diagnostic pitfalls.

MATERIAL AND METHODS

Histological features analyzed in 66 AFXs were: ulceration, morphological variants, growth pattern, location in the skin and vascular/perineural invasion. The antibodies used were CK-MNF116, CK-AE1/AE3, S100, smooth muscle actin, desmin, CD31 and EMA.

RESULTS

The study included 59 males, 7 females, aged 55-95 years, mean 77 years. All developed on sun damaged skin. Ulceration was present in 50%. Morphological patterns were pleomorphic spindle and epithelioid cells (60.6%), predominantly spindle cells (19.7%), purely spindle-cells (13.6%), and predominantly epithelioid cells (6.1%). Most were localized in the dermis (57.6%). An expansile (36.4%) rather than infiltrative (6.1%) growth into superficial subcutis was also noted. No vascular/perineural invasion was seen. Additional changes were hemorrhagic and pseudoangiomatous areas (24.2%), granular cell change (22.7%), keloid-like areas (9.1%), myxoid change (7.6%), osteoclast-like giant cells (6.1%) and clear cell change (4.6%). AFXs were consistently negative for S100, CK-MNF116, CK-AE1/AE3 and desmin. Focal positivity for SMA (45.2%), EMA (24.4%) and CD 31 (9.5%) was seen.

CONCLUSIONS

A diagnosis of AFX is still made by exclusion of other malignant neoplasms with similar morphology. Immunohistochemistry plays a crucial role in this distinction, but can also be misleading. This study expands the spectrum of non-vascular CD31 positive tumors.

Aspects of the differential diagnosis of clear-cell lesions of the skin in connection with the rare case of a clear-cell atypical fibroxanthoma

Clear-cell changes are rare in histological specimens of the dermis and raise complex diagnostic considerations regarding lineage differentiation (e.g., epithelial, mesenchymal, or melanocytic). We present a clear-cell atypical fibroxanthoma (CCAFX) and describe the morphological and immunohistochemical aspects of this rare skin lesion. Furthermore, we give an overview of the differential diagnoses of clear-cell lesions of the skin for a practical approach.

Atypical fibroxanthoma

Atypical fibroxanthoma (AFX) is a nodular dermal ulcerative lesion with a favorable prognosis. AFX most commonly occurs on sun-exposed skin in elderly individuals. AFX is characterized by its association with ultraviolet radiation, not only from a clinical aspect, but also from a molecular aspect. Making a diagnosis of AFX is challenging, and it is important to differentiate it from squamous cell carcinoma and malignant melanoma. Histological features and combined immunohistochemical markers are necessary for a definitive diagnosis (i.e., an absence of immunostaining for cytokeratins, S100 and HMB45 in AFX is helpful for excluding both squamous cell carcinoma and malignant melanoma). AFX, as well as MFH (malignant fibrous histiocytoma), is a fibrohistiocytic lesion with myofibroblastic differentiation. AFX is considered to be a different lesion from MFH. AFX and MFH might share the same pathway which determines their morphology. However, they may have different pathways in development which determine their biological behavior.

Adnexal clear cell carcinoma with comedonecrosis: clinicopathologic analysis of 12 cases

CONTEXT

Cutaneous clear cell tumors can pose a diagnostic challenge even to the experienced dermatopathologist; this is partly because of limitations of existing diagnostic categories.

OBJECTIVE

To describe a previously unrecognized, distinctive cutaneous adnexal carcinoma capable of an aggressive clinical course.

DESIGN

Clinicopathologic analysis of a series of 12 cases.

RESULTS

The patients were older individuals (median age, 71 years) with equal gender frequency. The lesions showed wide anatomic distribution with predilection for the head and neck area, especially the scalp. The lesions presented as rapidly growing, erythematous to flesh-colored, solitary papules/nodules that were capable of quickly reaching a size of several centimeters. Histologically, adnexal clear cell carcinoma with comedonecrosis was characterized by dermal proliferation of nests of epithelial cells showing distinctive zonal arrangement. The periphery of the tumor nests was formed by squamoid cells merging with centrally located clear cell areas containing foci of comedonecrosis. The lesions often showed multilobular or trabecular growth pattern and infiltrating border. Nuclear pleomorphism was variable; mitotic count ranged from 2 to 32/mm2 (median, 8/mm2). No ductal, cuticular, or apocrine differentiation was seen. All cases showed expression of epithelial membrane antigen and cytokeratin 17 in clear cells, with focal carcinoembryonic antigen expression in some cases. Follow-up (average, 37 months) revealed local recurrence (4 cases) and regional and distant metastases (2 cases).

CONCLUSIONS

Adnexal clear cell carcinoma with comedonecrosis appears to be a distinctive adnexal neoplasm that has to be distinguished from more indolent squamous cell and tricholemmal carcinomas.

Cutaneous Balloon Cell Dermatofibroma (Fibrous Histiocytoma)

Dermatofibroma (DF) or cutaneous fibrous histiocytoma is a common benign skin tumor that exhibits multiple, distinct histologic variants. Although clear cell DF has been described in the literature, balloon cell degeneration causing a clear cell DF phenotype has been not been reported to date. Herein, we describe the clinicopathologic findings of balloon cell DF arising on the heel of a 43-year-old man. Clinically, it presented as enlarging tan-white, ulcerated, firm 1.5 cm nodule, clinically suspected to be pyogenic granuloma. Excisional biopsy revealed a circumscribed fibrous tumor populated by mostly clear and spindle cells. A zonal arrangement separated the varied tumor cells where the most superficial, polypoid area showed large, clear polygonal balloon cells; the mid-dermal zone demonstrated a transition between balloon cells, epithelioid cells, and spindle cells; and the deep dermal zone had storiform arrangement of spindle cells, with the fascicles separated by coarse collagen bundles. A CD10+ > CD68+ > Factor XIIIa+ immunophenotype was identified with negative immunolabeling for S-100 protein, HMB-45, cytokeratin AE1/AE3, desmin, smooth muscle actin, lysozyme, and leukocyte common antigen (LCA). Ultrastructurally, the clear tumor cells were filled with multiple, empty, nonmembrane bound vacuoles of varying size. No recurrence has been described after complete excision and 7 months of follow up. DF with balloon cell change, likely secondary to persistent irritation, should be added to the differential diagnosis of cutaneous primary and metastatic neoplasms showing balloon cell degeneration such as balloon cell melanocytic nevi and renal cell carcinoma, respectively.

Granular Cell Atypical Fibroxanthoma: Report of Two Cases

Two cases of an uncommon histopathological variant of atypical fibroxanthoma (AFX) are described. Even though both lesions presented as clinically conventional atypical fibroxanthoma, histopathology disclosed a neoplasm composed of cells with granular change that was negative for S100 staining, and showed prominent pleomorphism, severe nuclear atypia, and a high mitotic index. Degenerative change may explain the granular phenotype in these two cases of AFX. The differential diagnosis with primitive nonneural granular cell tumor is discussed.

Peritoneal metastases from an atypical fibroxanthoma

Atypical fibroxanthoma (AFX) is a mesenchymal neoplasm usually occurring in sun-exposed skin of elderly patients. The majority have an excellent prognosis, as recurrences are uncommon and metastases are rare. We present a case of an 81-year-old man who developed widespread peritoneal metastases from an AFX on his scalp, which was completely excised 3 years earlier. Histology of the scalp lesion showed a markedly pleomorphic neoplasm characteristic of AFX. Features associated with increased risk of metastasis, namely lymphovascular space invasion, deep invasion, and substantial necrosis, were not present. An extensive immunohistochemical panel was performed. The tumor cells were negative for melanocytic, epithelial, and smooth muscle immunohistochemical stains, and positive for vimentin, CD10, CD99, and focally for CD68. Histologically, the peritoneal tumor was virtually identical to the original scalp lesion and had an identical immunohistochemical profile. Electron microscopy of the peritoneal tumor revealed pleomorphic undifferentiated cells with abundant lipid vacuoles. This is the first reported case of AFX with peritoneal metastases. Although AFXs generally have an excellent outcome, pathologists must remain cognizant of the small but real potential for metastasis and this needs to be conveyed in all reports.

Atypical fibroxanthoma with perineural or intraneural invasion: report of two cases

We report two cases of atypical fibroxanthoma (AFX) that both had the previously unreported feature of neural invasion (one perineural and the other intraneural). AFXs recur in approximately 10% of cases but only rarely metastasize. Features associated with recurrence are inadequate excision and invasion into fat. Features associated with metastasis include recurrence, vascular invasion, deep tissue invasion, and tumor necrosis. Both of these tumors invaded deeply into subcutaneous fat and reached the deep fascia. Some authors would regard such cases as malignant fibrous histiocytoma (MFH) because of such deep extension; however, the concept of AFX as a superficial variant of MFH is outmoded--AFX is a distinct clinicopathologic entity with established clinical, histological, and immunohistochemical features.

Clear cell atypical fibroxanthoma - report of a case with review of the literature

Clear cell atypical fibroxanthoma (CCAFX) is a rare variant of atypical fibroxanthoma (AFX), a pleomorphic dermal tumour associated with a good prognosis. A 67-year-old man presented with a rapidly growing nodule on the ear, which had appeared over a 2-week period. Sections showed an ulcerated nodule composed of pleomorphic spindled and polygonal cells with clear cytoplasm, invested by a delicate vascular stroma, reminiscent of clear cell renal cell carcinoma. Numerous mitotic figures were seen. The tumour cells stained with vimentin, CD68 and CD99 and were cytokeratin-negative. The immunohistochemical and ultrastructural features supported a diagnosis of CCAFX. The diagnosis of CCAFX requires the exclusion of other pleomorphic clear cell tumours that can occur in the skin by using a combination of morphology, immunohistochemistry and electronmicroscopy. Murali R, Palfreeman S. Clear cell atypical fibroxanthoma - report of a case with review of the literature.

Malignant adnexal neoplasms

Malignant cutaneous adnexal neoplasms are one of the most challenging areas of dermatopathology. Tumors of the pilosebaceous apparatus can occur as single-lineage neoplasms or may manifest as complex proliferations with multilineal differentiation patterns including not only the germinative component of the hair bulb, the inner or outer root sheath epithelium and the sebaceous gland and duct, but also the sweat duct components that relate to the apocrine secretory apparatus which empties into the follicle near the follicular bulge. Eccrine and apocrine neoplasms present a bewildering array of morphologies, which often defy precise classification. The purpose of this review is to discuss in detail the malignant neoplasms of the cutaneous adnexae and their benign and prognostically indeterminate mimics.

Cutaneous clear cell myomelanocytic tumour: a new member of the growing family of perivascular epithelioid cell tumours (PEComas). Clinicopathological and immunohistochemical analysis of seven cases

AIMS

To analyse seven cases of cutaneous myomelanocytic tumour histologically and immunohistochemically. Perivascular epithelioid cell tumours (so-called PEComas) are rare and recently delineated neoplasms occurring in the lung, kidney, pancreas, uterus, falciform ligament, vulva, heart, prostate and soft tissues. PEComas are characterized by a perivascular location of neoplastic cells showing a broad spectrum of epithelioid and spindled cells with clear, and granular pale eosinophilic cytoplasm, and a variable expression of melanocytic and muscle markers, whereas S100 protein and cytokeratins are usually absent.

METHODS AND RESULTS

We report seven cases of cutaneous myomelanocytic tumour arising on the lower (six cases) and upper (one case) extremities of female adults (age range 30-66 years). In all cases an ill-defined dermal lesion with extension into subcutaneous tissue was noted. The neoplasms contained numerous blood vessels with a lace-like pattern and slightly thickened vessel walls, and were composed of perivascular epithelioid cells containing clear or focally granular pale eosinophilic cytoplasm and round vesicular nuclei with small, sometimes slightly enlarged nucleoli. Increased proliferative activity and tumour necrosis were not seen. Immunohistochemically, tumour cells stained positively for HMB-45, microphthalmia transcription factor, and NKIC3 in all cases, whereas perivascular expression of alpha-smooth muscle actin and focal positivity for desmin were noted in one case each only. Two out of four cases tested stained focally positive for calponin. No expression of S100 protein and pancytokeratin was present. Despite incomplete/marginal excision in three cases none of the neoplasms has recurred locally so far.

CONCLUSIONS

With the presented series of cutaneous myomelanocytic tumours the clinicopathological spectrum of PEComas is expanded.

Fibroxantoma atípico. Estudio clinicopatológico de 10 casos

INTRODUCTION

Atypical fibroxanthoma (AFX) is a rare tumor of unknown histogenesis, considered by most authorities as a superficial form of malignant fibrous histiocytoma (MFH). The aim of this work is to report the clinicopathological features of 10 cases of AFX.

MATERIAL AND METHODS

Data were retrospectively collected of the computerized medical history. Clinical (age, onset-diagnosis time, location, accompanying pathology, outcome), histological (architectural pattern, cell type, ulceration, vascular or perineural invasion, subcutis involvement, pleomorphism, mitosis, inflammatory infiltrate) and immunohistochemical variable were analyzed.

CASES REPORT

Clinical and epidemiological features coincide with those previously reported: onset late in life, short time onset-diagnosis, involvement of skin with notable sun damage and a good outcome. Pathologically all the cases showed a spindle-cell prevalence arranged in a vaguely storiform pattern, along with both, multinucleated and eosinophilic cells.

DISCUSSION

The diagnosis of AXF is always of exclusion. Other spindle-cell tumors such as squamous cell carcinoma, malignant melanoma, leyomiosarcoma or dermatofibrosarcoma protuberans must be ruled out by immunohistochemical techniques. In spite of its rarity, the recognition of AFX is important in order to avoid inappropriately aggressive treatment.

Granular cell atypical fibroxanthoma

We report on two patients with granular cell atypical fibroxanthoma. Both neoplasms were solitary, light-tan, dome-shaped papules on sun-exposed areas of the head in two elderly white men. Microscopically, these neoplasms showed a dermal proliferation of pleomorphic granular cells with irregular hyperchromatic nuclei, multinucleated cells, and scattered mitoses. Immunohistochemical stains were positive for CD68 and vimentin and negative for Melan-A or human melanoma black (HMB)-45, S-100 protein, pancytokeratin, and actin, consistent with atypical fibroxanthoma. The differential diagnosis of granular cells in neoplasms containing cytological pleomorphism is challenging in view of the many different neoplasms that may present with granular cytoplasm. These include the conventional granular cell tumor and its malignant form, leiomyoma, leiomyosarcoma, dermatofibroma, dermatofibrosarcoma protuberans, and angiosarcoma.

[Clear cell dermatofibroma: a case report with cytogenetic study]

We report an observation concerning a 48-year-old male who presented with a 5 cm tumour on his left leg, first noticed 18 months ago. The remainder of clinical examination was normal. Histological assessment revealed a tumoral infiltration of entire dermis and superficial hypodermis. This tumour consisted of monomorphous, ovoid or spindle cells, with clear cytoplasm and PAS+ granulations. There was strong immunoreactivity by tumoral cells only for vimentin. Ultrastructural studies revealed fibrohistiocytic-like tumoral cells, without epithelial, muscular, vascular or melanocytic differentiation. These results were consistent with the diagnosis of clear cell dermatofibroma. Cytogenetic evaluation and FISH analysis showed a deletion of p12. Clear cell dermatofibroma is a rare and recent variant of dermatofibroma, with a difficult histological evaluation and which must be differentiated from clear-cell sarcoma. This observation is the first case-report of this entity, to our knowledge, showing a cytogenetic abnormality.

Distinctive dermal clear cell mesenchymal neoplasm: clinicopathologic analysis of five cases

Dermal clear cell tumors are not common. This group of lesions is comprised primarily of clear cell adnexal lesions, balloon cell melanocytic lesions, and metastatic clear cell carcinomas. We report the clinicopathologic features of five cases of a novel dermal clear cell neoplasm that appears mesenchymal in nature. The affected patients included 3 men and 2 women ranging in age from 38 to 70 (median, 45 years). All the lesions occurred on the lower limb. Clinically described as smooth cutaneous nodules, size ranged from 0.5 to 2.5 cm in greatest dimension and the lesions were present from weeks to 5 years prior to excision. Situated in the reticular dermis, the tumors usually extended to involve the subcutis with sparing of the papillary dermis. The tumors were composed of large optically clear cells with vesicular nuclei. The lesions entrapped adnexal structures and thin dermal collagen fibers. Mitoses were rare (less than 1 per 25 hpf). A single case showed more pleomorphic nuclei as well as quite frequent mitoses and was considered of uncertain biologic potential. Immunohistochemistry revealed reactivity only for NKI-C3 (5/5 cases), CD68 (2/5 cases), and vimentin (2/3 cases); melanocytic, epithelial, and lymphoid markers were uniformly negative. All five lesions were locally excised; the more pleomorphic and mitotically active lesion was widely re-excised and given subsequent radiation therapy. In follow-up ranging from 1.5 to 11 years (median, 5.5 years), none of these lesions has recurred. These tumors appear to be mesenchymal in nature, but their precise line of differentiation is unknown. Recognition of these lesions is important to avoid confusion with better-known malignant neoplasms.

Primary purely intradermal pleomorphic liposarcoma

INTRODUCTION

Pleomorphic liposarcoma (PLPS) is a high-grade pleomorphic sarcoma, containing multivacuolated lipoblasts, which usually develops during late adult life. It usually occurs in the deep soft tissues and uncommonly arises in the subcutis, the dermis representing an exceedingly rare site of occurrence.

METHODS

We describe a case of PLPS arising in the dorsal aspect of the nose of a 75-year-old woman. Preoperative duration was 9 months.

RESULTS

The lesion was intradermal well-circumscribed, dome-shaped, measuring 1.2 cm. It fulfilled the histologic criteria for inclusion in the PLPS category. The tumor cells focally expressed calretinin. A review of the literature yielded four cases documented, to which we add the present report. All the patients were adults with a mean age of 67 (range 39-95) years, and three of five cases arose on the scalp. Local recurrence occurred in one patient, but no distant metastases or disease-related deaths were observed.

CONCLUSION

PLPS very rarely arises in the dermis. In spite of high-grade morphology, the intradermal tumor shows a relatively favorable prognosis. Diagnostic consideration includes pleomorphic lipoma, clear cell atypical fibroxanthoma, balloon cell melanoma, and metastatic clear cell carcinoma of renal origin. Recognition of this distinctive and rare type of liposarcoma is essential to avoid under- or misdiagnosis and inappropriate treatment.

Sebaceous carcinoma and the T-antigen

Carcinomas of sebaceous glands are uncommon. They are traditionally classified into ocular and extraocular sebaceous carcinomas (SC). Ocular SC tend to be more common and more aggressive than extraocular SC. However, the latter can occasionally follow a fatal course. Histologically, SC should be classified into 1) SC in situ; 2) SC, infiltrating, low-grade with or without pagetoid spread; 3) SC, infiltrating, high-grade, with or without pagetoid spread; and 4) SC with extraocular and extracutaneous involvement, including metastases. Immunohistochemistry plays a minor role in the diagnosis of SC. Thomsen-Friedenreich (T) antigen can be a helpful tool in differentiating SC (strong T-antigen reactivity in basaloid cells) from other mimicking neoplasms (basaloid cells are T-antigen negative). The histologic differential diagnosis, pathogenesis, and management of SC are reviewed.