AIMS: Based on a series of 25 cases, we define and characterize combined dermatofibroma, a tumour comprising two or more variant patterns of dermatofibroma in a single lesion. METHOD AND RESULTS: Dermatofibroma may present with a wide variety of architectural, cellular or stromal peculiarities. Architectural peculiarities include deep penetration, atrophy, collarette formation, fascicular to plexiform architecture, massive haemorrhage, prominent haemangiopericytoma-like vascularity and palisading; cellular peculiarities the presence of epithelioid cells, clear cells, granular cells, prominent myofibroblastic differentiation and atypical giant cells ('monster cells'); or stromal peculiarities such as prominent sclerosis, mucin, haemosiderin and cholesterotic deposits. In combined dermatofibromas two or more of these features are seen in complex or inhomogenous combination such as the silhouette of a deep penetrating dermatofibroma with an 'ordinary' storiform pattern in the upper and granular cell differentiation in the lower part of the lesion; or a dermatofibroma with ordinary features in the upper, prominent sclerosis in the middle and clear cells in the lower portion of the lesion; or the characteristic epidermal collarette and cells of epithelial cell histiocytoma with a plexiform ('neurothekeoma-like') architecture surrounded by a myxoid stroma with spindle-shaped to stellate cells. Clinically, these lesions preferentially occur on the lower extremities of young to middle-aged females, frequently with the diagnosis of a fibrohistiocytic lesion. Apart from one recurrence follow-up was uneventful in all other cases. Immunohistochemically, lesions are consistently positive with KiM1p, variably positive for factor XIIIa, smooth muscle specific actin and with KP1 (CD68), NK1C3 and E9. CONCLUSION: Recognition of combined dermatofibroma allows the histopathologist to apply a confident benign label to unusual lesions which might otherwise elude diagnosis, or tempt description of 'new' entities and to avoid a misdiagnosis of malignancy.

Actins↗

PubMed2000

Expression of Fas and Fas ligand after experimental traumatic brain injury in the rat.

Apoptotic cell death plays an important role in the cascade of neuronal degeneration after traumatic brain injury (TBI), but the underlying mechanisms are not fully understood. However, increasing evidence suggests that expression of Fas and its ligand (FasL) could play a major role in mediating apoptotic cell death in acute and chronic neurologic disorders. To further investigate the temporal pattern of Fas and FasL expression after experimental TBI in the rat, male Sprague Dawley rats were subjected to unilateral cortical impact injury. The animals were killed and examined for Fas and FasL protein expression and for immunohistologic analysis at intervals from 15 minutes to 14 days after injury. Increased Fas and FasL immunoreactivity was seen in the cortex ipsilateral to the injury site from 15 minutes to 72 hours after the trauma, respectively. Immunohistologic investigation demonstrated a differential pattern of Fas and FasL expression in the cortex, respectively: increased Fas immunoreactivity was seen in cortical astrocytes and neurons from 15 minutes to 72 hours after the injury. In contrast, increased expression of FasL was seen in cortical neurons, astrocytes, and microglia from 15 minutes to 72 hours after impact injury. Concurrent double-labeling examinations using terminal deoxynucleotidyl transferase-mediated deoxyuridine-biotin nick end labeling identified Fas- and FasL-immunopositive cells with high frequency in the cortex ipsilateral to the injury site. In contrast, there was no evidence of Fas- and FasL-immunopositive cells in the hippocampus ipsilateral to the injury site up to 14 days after the trauma. Further, Fas and FasL immunoreactivity was absent in the contralateral cortex and hippocampus at all time points investigated. These results reveal induction of Fas and FasL expression in the cortex after TBI in the rat. Further, these data implicate an involvement of Fas and FasL in the pathophysiologic mechanism of apoptotic neurodegeneration after TBI. Last, these data suggest that strategies aimed to repress posttraumatic Fas- and FasL-induced apoptosis may open new perspectives for the treatment of TBI.

Animals↗

PubMed2000

Perineuroma. A frequently unrecognized entity with emphasis on a plexiform variant.

AIMS: The present series describes six cases of perineurioma, a rare and frequently unrecognized entity, including one case with an unusual plexiform growth pattern. METHODS: Retrospective clinicopathologic study of six perineuriomas. RESULTS: All lesions occurred on the upper extremities or shoulders of adults, five in females. Histologically, all six cases of perineurioma had been initially unrecognized or misdiagnosed as dermatofibroma, fibroma of tendon sheath, neurofibroma, schwannoma, or naevus, respectively. Scanning magnification revealed well circumscribed, dermal to subcutaneous lesions without capsule formation. Besides characteristic onion bulbs", i.e. concentric whorls of epithelioid to spindle-shaped cells, there was great variation of histomorphologic features: single nodules or plexiform architecture; a few to many concentric whorls; five to several dozens of cell layers in concentric whorls; high to low cellularity; round/oval to spindle-shaped/wavy cells/nuclei; delicate to prominent collagen; variable mucin, sclerosis, and/or intralesional clefts. Immunohistochemically, all lesions were consistently positive for EMA, ultrastructurally (1 case) with evidence of perineurial differentiation such as slender and elongated, bipolar cytoplasmic processes with discontinuous basal lamina, prominent pinocytosis and desmosome-like junctions. CONCLUSION: Our series documents that cutaneous and subcutaneous perineurioma is frequently unrecognized or misinterpreted and may occasionally show a plexiform growth pattern. The differential diagnosis of plexiform variants includes a variety of plexiform lesions such as naevi, neurofibroma, schwannoma, etc. Historically, similar plexiform lesions seem to have been published as nerve sheath myxoma/neurothekeoma, Pacinian neurofibroma or perineurial myxoma. This terminology is imprecise and confusing and, thus, should be avoided in favour of the correct term of perineurioma.

Adult↗

PubMed1999

Myxoid dermatofibroma.

AIMS: This report presents seven cases of a rare variant of dermatofibroma, characterized by marked mucinous stromal changes. METHODS AND RESULTS: In this retrospective clinicopathological study, lesions preferentially occurred on the lower extremities of young to middle-aged females. Clinical (differential) diagnoses included: dermatofibroma (two cases), cyst, tophus, ganglion and neurofibroma. Histology revealed well circumscribed, faintly stained dermal to subcutaneous lesions which contained abundant stromal mucin. A variable amount of spindle-shaped cells, occasional lymphocytes and fine collagen fibres were also seen. Epidermal hyperplasia above as well as storiform arrangement of spindle cells and some sclerotic collagen at the periphery of the lesion indicated the fibrohistiocytic origin. Individual histopathological features included: bizarre giant cells, perifollicular arrangement and seas of mucin with pseudovascular clefts in one case each. Immunohistochemically, all lesions were positive for KiM1p (> 50% of the cells). Moreover, two lesions showed moderate reactivity for factor XIIIa (10-25%), one each with NK1C3 (> 90%) and smooth muscle actin (50%), but were otherwise negative with a broad panel of markers. Electron microscopy in one case revealed large pools of mucin interspersed by a moderate number of fibrocytes with fine fibrillary collagen. CONCLUSION: This series confirms myxoid dermatofibroma as a rare variant of fibrohistiocytic tissue response; our series also indicates that many of these lesions might be misinterpreted as cutaneous myxoma.

Adult↗

PubMed1999

Giant cell atypical fibroxanthoma: does it really exist?

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Aged↗

PubMed1999

Differential expression of CD34 and Ki-M1p in pleomorphic fibroma and dermatofibroma with monster cells.

Pleomorphic fibroma (PF) and dermatofibroma with monster cells (DFMC) are characterized by the presence of numerous cells with large atypical nuclei. Despite cytologic similarities, the two entities are likely to be unrelated, but their histogenesis is poorly understood. In this study, we examined six cases of PF and eleven cases of DFMC by immunohistochemistry using antibodies against vimentin, alpha-smooth muscle actin, S-100 protein, CD34, factor XIIIa, and the pan-monocytic marker Ki-M1p. Strong vimentin expression was seen in all tumors, whereas none of them expressed S-100 protein. PF consistently exhibited CD34 staining but appeared to be depleted of Ki-M1p positive cells compared with the surrounding normal skin. Conversely, all cases of DFMC contained numerous Ki-M1p positive cells including atypical multinucleate cells, but virtually no CD34 reactivity was observed. A weak staining for alpha-smooth muscle actin was occasionally seen in a subset of the cells of both entities. Our results indicate that PF and DFMC are histogenetically distinct entities that may arise from two different types of dermal dendritic cells defined by their reactivity for CD34 and Ki-M1p, respectively. Immunohistochemistry using these two antibodies permits an easy and reliable discrimination between PF and DFMC.

Actins↗

PubMed1999

Polypoid dermal hemangiopericytoma? An alternative point of view.

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Diagnosis, Differential↗

PubMed1998

[Non-Langerhans-cell histocytosis].

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Adult↗

PubMed1998

[Dermatofibroma. A clinico-pathologic classification scheme].

Dermatofibroma is a common benign fibrohistiocytic lesion which presents with a wide variety of clinicopathologic variants. This may cause great difficulties in delineation from a variety of benign and malignant tumours. According to their peculiarities we differentiate: 1. Dermatofibromas with architectural peculiarities like deep penetrating, atrophic, giant, aneurysmal ("angiomatoid"), haemangiopericytoma-like, palisading or ossifying variants. 2. Dermatofibromas with cellular/stromal peculiarities like clear cell, granular cell, myofibroblastic, sclerotic, monster cell, atypical ("pseudosarcomatous"), elusive ("haemosiderotic"), cholesterotic, and myxoid variants. 3. Dermatofibromas with architectural and cellular/stromal peculiarities in homogenous arrangement like epithelioid cell, cellular benign variants, with smooth muscle proliferation, basal cell carcinoma-like, pseudolymphomatous, multinucleate cell angiohistiocytoma, cellular neurothekeoma, plexiform fibrohistiocytic tumour, plexiform xanthoma and plexiform xanthomatous tumour. 4. Complex or composite dermatofibromas with two or more architectural and cellular/stromal peculiarities in inhomogenous arrangement, e.g. silhouette of an epithelioid cell histiocytoma with plexiform fascicles of cellular neurothekeoma and granular cell features.

Histiocytoma, Benign Fibrous↗

PubMed1998

Vulval and vaginal adenosis.

Vaginal adenosis is defined by the presence of metaplastic cervical or endometrial epithelium within the vaginal wall, thought to be derived from persistent Müllerian (synonymous with paramesonephric) epithelium islets in postembryonic life. Spontaneous vaginal adenosis appears to be a fairly common (present in about 10% of adult women) but mostly insignificant coincidental finding. In women prenatally exposed to diethylstilboestrol (DES), vaginal adenosis may arise in up to 90% and is associated with a high risk of vaginal carcinoma. Since the withdrawal of DES from the market, vaginal adenosis has virtually disappeared from the medical literature. A case of vaginal adenosis is presented in a middle-aged woman who had not been prenatally exposed to DES. The lesions differed from the spontaneous type by their sudden appearance, their extent and their pronounced subjective symptoms. It is speculated that protracted oral contraceptive intake may have played a causative role.

Adult↗

PubMed1998

Scalloped cell xanthogranuloma.

AIMS: We describe nine cases of scalloped cell xanthogranuloma, a distinct solitary variant of non-Langerhans cell histiocytoses. METHODS AND RESULTS: In this retrospective clinicopathological study scalloped cell xanthogranuloma mostly occurred on the back or head and neck of young adult males diagnosed as a xanthogranuloma, naevus, or basal cell carcinoma. Histology characteristically revealed a sheet-like infiltrate of predominantly scalloped histiocytes (> 79% of all cell types) in the upper dermis. Other mononuclear (vacuolated, xanthomatized, spindle-shaped, oncocytic) and multinucleate (foreign body, ground glass and Touton) histiocytes were also regularly seen. Immunohistochemically, all cases exhibited a macrophage/dendritic cell lineage positive with KP1 (CD68), KiM1p, HAM 56 and factor XIIIa. Ultrastructurally, numerous intracytoplasmic dense, occasionally also myeloid bodies were present. No associated systemic disease, hyperlipidaemia or recurrence were seen during follow-up. CONCLUSIONS: These findings are similar to those of early lesions of xanthoma disseminatum: thus, scalloped cell xanthogranuloma could be regarded as a solitary counterpart of xanthoma disseminatum, and, moreover, fits neatly into a unifying concept of non-Langerhans cell histiocytoses.

Adolescent↗