Dermatofibroma parasitized by Leishmania in HIV infection: a new morphologic expression of dermal Kala Azar in an immunodepressed patient

Visceral leishmaniasis is a protozoan infection that may complicate the course of patients with human immunodeficiency virus (HIV). Dermatofibroma is a cutaneous fibrohistiocytic lesion considered neoplastic by some authors and inflammatory by others. Eruptive dermatofibromas have been described in patients with HIV infection or with other altered immunity situations. We present the case of a 32-year-old, HIV-positive man with visceral leishmaniasis who complained of the appearance of a cutaneous lesion in the leg formed by the coexistence of dermatofibroma and Leishmania parasitic colonization. As far as we know, this type of association has not been reported previously. We consider that the dermatofibroma could have developed as an unusual form of fibrohistiocytic reaction to leishmania. From a practical approach, we recommend the search of leishmaniasis in dermatofibroma in immunosuppressed patients.     

A case of polypoid dermatofibroma

Dermatofibroma is a common benign cutaneous tumor that usually appears as a slowly growing firm nodule. Polypoid nodular dermatofibroma is a variant type that is rarely encountered. We reported a case of polypoid dermatofibroma with a review of the previously reported cases. Polypoid dermatofibroma tends to arise on the leg, especially below the knee. Its size is often larger than that of common dermatofibroma. It is speculated that both the underlying firm tissue and long-term development may lead the tumor to form a polypoid appearance.     

Dermatofibroma in a black tattoo: report of a case

Tattooing has been associated with a variety of complications including inflammatory and granulomatous reactions, transmission of infections, and neoplasms. We report a case of a 24-year-old male who presented with a 2-month history of an erythematous nodule involving a newly made tattoo on the right leg. An excisional biopsy was performed and the histopathological evaluation was consistent with dermatofibroma. Only three cases of dermatofibroma associated with tatooing were reported in litetature. We report an additional case and review the literature regarding cutaneous reactions to tattoos.     

Dermoscopic findings of haemosiderotic and aneurysmal dermatofibroma: report of six patients

BACKGROUND: The clinical diagnosis of dermatofibroma is commonly easy. However, the differentiation of dermatofibroma from other cutaneous tumours is difficult in some instances, primarily in atypical cases and rare variants. Haemosiderotic dermatofibroma is a variant composed of numerous small vessels, extravasated erythrocytes and intra- and extracellular haemosiderin deposits. Aneurysmal dermatofibroma is a variant composed of large, blood-filled spaces without endothelial lining. Some authors consider that haemosiderotic dermatofibroma is an early stage in the development of aneurysmal dermatofibroma. The clinical differential diagnosis of haemosiderotic or aneurysmal dermatofibroma must include melanoma and other melanocytic tumours, vascular neoplasms, adnexal tumours and nonspecific cysts. Dermoscopy improves the diagnostic accuracy in pigmented and nonpigmented skin lesions. OBJECTIVES: To evaluate specific dermoscopic criteria. METHODS: Dermoscopic examination (using the DermLite Foto; 3Gen, LLC, Dana Point, CA, U.S.A.) of six patients with haemosiderotic or aneurysmal dermatofibromas was performed to evaluate specific dermoscopic criteria. RESULTS: A multicomponent pattern with a central bluish or reddish homogeneous area in combination with white structures and a peripheral delicate pigment network along with vascular structures was noted in five of six lesions. CONCLUSIONS: This dermoscopic pattern yielded the diagnosis of haemosiderotic or aneurysmal dermatofibroma in most cases. However, this multicomponent pattern may present in some melanomas and although it is useful in determining a clinical diagnosis of aneurysmal dermatofibroma, it may not be specific to this entity.     

Dermatofibroma with monster cells

Nineteen cases of dermatofibroma associated with monster cells are reported. The term "monster" (an animal with a strange or terrifying shape, one unusually large for its kind) implies a strikingly atypical cell with an extremely large nucleus. Except for monster cells, these 19 lesions had all of the typical histopathological findings of dermatofibroma. The clinical diagnosis for 16 of these lesions was dermatofibroma (or histiocytoma). Three lesions were submitted without any clinical diagnosis. Eighteen of 19 lesions occurred on the extremities. One was on the back. Monster cells are seen in the early, histiocytic stage of dermatofibroma when lipophages and/or siderophages are usually present in large numbers. Only rarely were mitotic figures seen in dermatofibromas with monster cells, and they were neither numerous nor atypical. It is important for histopathologists to distinguish dermatofibroma with monster cells from cutaneous malignant fibrous histiocytoma and radiation sarcoma. The criteria for differentiation concern primarily the architectural pattern of the lesion rather than its cytological features.     

Reticulohistiocytosis: different dermatoscopic faces and a good response to methotrexate treatment

The reticulohistiocytoses are a rare group of non‐Langerhans cell histiocytic disorders. Recently, dermatoscopic features have been reported for some of the xanthomatous disorders. We report a case of diffuse cutaneous reticulohistiocytosis with 29 reticulohistiocytomas. On dermatoscopy of these lesions, we saw three typical features: a homogeneous pattern with various shades of yellow (defined previously as a ‘setting‐sun’ pattern), brown reticular structures, and central white scar‐like patches and streaks. The setting‐sun pattern was most commonly seen in combination with brown reticular structures. In four lesions, brown reticular structures surrounded a central white scar‐like patch resembling that of a dermatofibroma. However, the presence of the setting‐sun pattern in the background gave a different hue to that of the peripheral network seen in a dermatofibroma. A marked clinical improvement was associated with 6 months of systemic methotrexate treatment. Dermatoscopy may aid in the diagnosis of xanthomatous diseases. For this patient, methotrexate was beneficial.     

Atypical polypoid dermatofibroma: report of two cases

Two cases of a hitherto undescribed special variant of dermatofibroma are reported. A man and a woman, aged 57 and 52 years, respectively, had slowly growing cutaneous tumors on the lower extremities. The tumors were exophytic and polypoid, 10 and 6 cm in maximal diameters, respectively; they were covered by rough nonulcerated skin and were joined by a short pedicle to an indurated base. Histologic examination showed some features of an otherwise conventional dermatofibroma, whereas the polypoid component was hypercellular and showed striking atypia and scattered mitotic figures. After 32 and 28 months' follow-up, the lesions did not recur after surgical excision. We suggest the term atypical polypoid dermatofibroma to summarize the special clinicopathologic features of these tumors.     

Dermatofibroma with sclerotic areas resembling a sclerotic fibroma of the skin

BACKGROUND: Dermatofibromas are common benign tumors that occur as single or multiple nodules on the extremities in adults. Sclerotic fibroma of the skin (SFS) is a benign tumor characterized histopathologically by a well-demarcated, non-encapsulated dermal nodule composed of hypocellular, sclerotic collagen bundles with prominent clefts. The pathogenesis of these two conditions is still in dispute. METHODS: We present a case of dermatofibroma with sclerotic areas resembling a sclerotic fibroma of the skin and a review of the literature. RESULTS: The tumor showed a well-demarcated dermal, fibrocollagenous tumor with three different histopathological features. One-fourth of the lesion was consistent with dermatofibroma. Another area adjacent to dermatofibroma revealed hyalinized eosinophilic collagen bundles arranged in the characteristic interwoven pattern with prominent clefts, as is described in sclerotic fibroma of the skin. One-half of the lesion between the dermatofibroma and sclerotic fibroma showed transitional changes from dermatofibroma to sclerotic fibroma. CONCLUSION: According to these findings, the possibility that sclerotic fibroma is an ancient or degenerated stage of dermatofibroma cannot be completely ruled out, but some authors still consider that dermatofibroma and sclerotic fibroma of the skin are completely different neoplasms.     

Sebaceous hyperplasia overlying a dermatofibroma

Epithelial changes overlying dermatofibromas are well recognized. The presence of sebaceous differentiation overlying a dermatofibroma is unusual. We report two patients with sebaceous hyperplasia overlying a dermatofibroma and discuss possible mechanisms for induction of the epithelium and adnexa by the mesenchyme in a dermatofibroma.     

Homogeneous blue pigmentation in dermatofibroma simulating a blue naevus

A case with a pigmented skin lesion that was diagnosed as a blue naevus on clinical and dermoscopic grounds and histopathologically confirmed as a dermatofibroma is presented. By means of this case, we define dermatofibroma as a new exception for 'homogeneous blue pigmentation' on dermoscopy.     

Dermatofibroma with granular cells: a report of two cases.

We describe two examples of an unusual variant of dermatofibroma (DF) in which areas of granular cells were a prominent feature. The diagnosis of DF was confirmed by immunohistochemistry and by ultrastructural studies. Granular cell changes can be observed in numerous benign and malignant cutaneous tumors of different cellular lineage. Cellular granularity is a nonspecific phenomenon characterized by intracytoplasmic accumulation of lysosomes and may cause diagnostic difficulties. Traumatic factors may be involved in the pathogenesis of cellular granularity.     

Basal cell carcinoma overlying a dermatofibroma

The epidermis over a dermatofibroma may show changes that range from simple hyperplasia to the proliferation of basaloid cells, which can become morphologically indistinguishable from basal cell carcinoma. The existence of a true basal cell carcinoma overlying a dermatofibroma is infrequent. These basaloid proliferations have usually been considered to be the result of the inductive effect of the fibrohistiocytic proliferation of the dermatofibroma on the epithelial cells of the hair follicle; therefore, it would be a reactive phenomenon and not truly neoplastic. We describe a case of dermatofibroma that presented with a basaloid proliferation identical in appearance to a basal cell carcinoma on the overlying epidermis.     

Atypical cutaneous fibrous histiocytoma

We report seven cases of atypical cutaneous fibrous histiocytoma, which appears to be a variant of cutaneous fibrous histiocytoma (dermatofibroma). These patients are all middle-aged women (mean, 39 years old) with small nodules occurring on the trunk and limbs. The lesions are characterized by marked focal cellular atypia, the absence of mitoses, and xanthomatous changes in both mononuclear and giant cells--all found within a small dermal nodule (approximately 1 cm) separated from an acanthotic epidermis by a Grenz zone. Their benign nature is demonstrated by the absence of recurrence, even after 9 years follow-up time.     

The Atrophic Dermatofibroma: A Delled Dermatofibroma

Atrophic dermatofibroma has been proposed as a term to designate a new and specific type of dermatofibroma. We report the clinical and histopathological findings in two cases of atrophic dermatofibroma. The peculiar morphology of these lesions simply represents a conspicuous example of the frequently seen central depression in dermatofibroma. On histopathology, no authentic atrophy is present, because the thinning of the dermis compared with that of the adjacent non-lesional skin results from this depression rather than from loss of tissue of the dermis. Delled dermatofibroma is a more appropriate appellation than atrophic dermatofibroma, because of the striking shape of these lesions.     

Sebaceous hyperplasia: a clue to the diagnosis of dermatofibroma

We describe a man with an indurated lesion on his upper back that showed a dermatofibroma with overlying sebaceous hyperplasia. Characteristic dermal features of a dermatofibroma may be sparse or absent in a lesional specimen that has been submitted subsequent to a superficial shave biopsy. Hyperplasia of sebaceous glands in a nonfacial lesion is a histologic feature that should prompt the search for a dermatofibroma in the underlying dermis.     

Tuberous sclerosis

Although tuberous sclerosis has been described with a diagnostic triad, it is not present consistently in all cases. Variety of skin manifestations were reported in tuberous sclerosis. This studay was undertaken to assess the frequency of various skin changes in tuberous sclerosis. Ten consecutive cases of tuberous sclerosis were studied. Angiofibroma was the commonest cutaneous manifestation. Atypical fibroxanthoma, dermatofibroma and neurofibroma were also noticed as interesting associations.     

Clear-cell variant of superficial cutaneous leiomyosarcoma associated with RB1 mutation: Clinical,dermoscopic, and histopathological characteristics

Leiomyosarcoma is a relatively rare soft tissue tumor whose clear-cell variant has only been reported in leiomyosarcomas of the uterus. We report here for the first time a primary cutaneous clear-cell leiomyosarcoma in the trunk skin of a 49-year-old man, characterized by a very indolent clinical and dermoscopic presentation, mimicking a dermatofibroma. Genetic analysis of the otherwise healthy patient revealed a germline mutation in the retinoblastoma 1 gene (RB1); the same mutation was found in his son, who had previously developed retinoblastoma. Moreover, the mother of the patient had died of uterine leiomyosarcoma with clear-cell changes. Mutations in the RB1 gene occur commonly in human neoplasms. In this patient, we were able to link his clear-cell variant of cutaneous leiomyosarcoma with the loss of retinoblastoma protein expression, as revealed by immunohistochemical staining analysis.     

Melanoma associated with a dermatofibroma

BACKGROUND: Dermatofibromas are common benign cutaneous fibrohistiocytic neoplasms, whereas melanomas are potentially aggressive malignancies. Differentiating these two entities can occasionally be difficult. METHODS: We report the case of a 56-year-old female presenting with a firm pink papule on the left thigh. RESULTS: Histopathology revealed atypical melanocytes in the epidermis and papillary dermis with numerous mitotic figures and intraepidermal pagetoid spread. Within the dermis was a poorly demarcated collection of epithelioid and spindled cells with intermixed keloidal collagen. The atypical melanocytes stained for MART-1 and S-100, whereas the underlying fibrohistiocytic tumor took up factor XIIIa immunostain, confirming the diagnosis of invasive malignant melanoma occurring in association with a dermatofibroma. CONCLUSIONS: This case emphasizes the role of immunohistochemical stains in correctly diagnosing melanocytic and histiocytic neoplasms.     

Multiple clustered dermatofibroma presenting in a segmental distribution

Multiple dermatofibromas is a rare entity consisting of more than fifteen lesions. Multiple clustered dermatofibroma is a distinct variant of multiple dermatofibromas and is defined as a well‐demarcated plaque composed of individual dermatofibromas. We report a 16‐year‐old boy with multiple clustered dermatofibroma in a segmental distribution, which has previously not been reported in the literature.     

Ulcerated dermatofibroma with osteoclast-like giant cells

Background: Ulceration and osteoclast-like giant cells are two pathological features uncommonly seen in dermatofibromas. To our knowledge, the presence of these features has not been previously described within the same lesion.
Methods: We report the clinical, histopathological and immunohistochemical findings of a 38-year-old man with an ulcerated dermatofibroma (DF) on the sole containing OLGC.
Comments: DF, or cutaneous fibrous histiocytoma, is a frequent dermatological lesion with many clinicopathological variants. Therefore, a correct diagnosis is not always straightforward, especially when two rare features co-exist in the same lesion. Differential diagnosis was performed with cutaneous and even non-cutaneous lesions. An explanation for the clinicopathological findings is also described.