Storiform collagenoma of the nail.

The term circumscribed storiform collagenoma was coined by Maize et al in 1989 to describe four dermal fibromas with pathologic features resembling the sclerotic fibromas associated with Cowden's disease. We report a subungual nodule with the pathologic features of circumscribed storiform collagenoma in a patient without Cowden's disease.     

Giant cell collagenoma: case report and review of the literature

BACKGROUND: Giant cell collagenoma (GCC) is a recently described cutaneous fibrous neoplasm that usually affects young to middle-aged adults. Despite its similar histological appearance with circumscribed storiform collagenoma, no association of GCC with Cowden's syndrome has been described so far. To the best of our knowledge only five cases of this rare fibrous tumor have been reported so far. METHODS: We report a case of a 79-year-old male patient presenting with a slow growing flesh-colored dome-shaped lesion in his left forearm, with a clinical diagnosis of fibroma. No stigma of Cowden's syndrome was depicted. RESULTS: The histological analysis showed a symmetrical and well-circumscribed flat-dome-shaped lesion covered by an atrophic overlying epidermis. The neoplasm was composed of hyalinized collagen bundles disposed in a whorled storiform pattern. Admixed with the collagen matrix, there were two distinct cell populations, one composed by spindle-shaped mononuclear cells, and the other composed by bizarre multinucleated giant cells. Immunohistochemical analysis showed positivity for vimentin and actin HHF35 in the mononucleated. The multinucleated cells only immunoexpressed vimentin. CONCLUSION: GCC is an unusual cutaneous fibrous tumor that should be differentiated from circumscribed storiform collagenoma, pleomorphic fibroma, regressive forms of dermatofibroma, and solitary myofibroma based on its histological features.     

席纹状胶原瘤

报告1例席纹状胶原瘤。患者男,46岁。背部肿物40年余,缓慢增长,无自觉症状。无系统性疾病病史。皮损组织病理检查示表皮轻度萎缩,真皮内可见一边界清楚的结节,无包膜,病变均匀、局限,由大量透明样变的胶原束组成,胶原束之间见许多裂隙,排列成席纹状。诊断:席纹状胶原瘤。     

Trichogerminoma

We report 14 cases of trichogerminoma, a rare form of cutaneous adnexal neoplasm, derived from hair germ epithelium. The neoplasms occurred in 9 men and 5 women. Their ages ranged from 16 to 73 years (median 53 years). The tumors were slow growing, asymptomatic dermal or subcutaneous nodules, located on the head and neck (6), trunk (4), extremities (2) and hip (1), with no distinguishing clinical features. Histologically, trichogerminomas were characterized by sharply circumscribed, pseudoencapsulated dermal and subcutaneous nodules, ranging in size from 0.4 to 4.0 cm in diameter (mean 1.9 cm). The nodules were subdivided into lobules separated by variable amounts of stroma that demonstrated varying cellularity and mucin content. The lobules were composed of basaloid cells that formed densely packed, round nests or "cell balls" resembling hair bulbs. The basaloid cells demonstrated peripheral palisading, keratinization and differentiation towards various pilosebaceous structures. Retraction spaces, well developed hair follicles and hair shafts were not observed. These distinctive histologic features separated these neoplasms from other tumors of pilar origin and from basal cell carcinoma. The trichogerminomas behaved in a benign fashion with one exception. Complete excision of the lesions is the treatment of choice.     

A distinctive type of widespread congenital melanocytic nevus with large nodules

We report an unusual case of congenital melanocytic nevus presenting in a 19-year-old African woman as widespread papules and variably sized nodules and tumors affecting the entire body, including the palms, soles, and oral mucous membrane. Histopathologic examination of 3 representative skin lesions showed mainly dermal aggregations of round to oval, focally pigmented, monomorphous melanocytes, arranged in nodular and plexiform patterns. Scattered areas with spindle-shaped dendritic melanocytes surrounded by fibrosis were also noted in the center of the lesions. The clinical and histopathologic findings were similar to those in 2 other previously reported cases, except that in 1 of the earlier cases the skin nodules were composed of spindle-shaped cells, suggesting a type of blue nevus. The findings in our case indicate a broader spectrum of morphologic features in this condition, with dermal aggregations of melanocytes showing congenital features, representing a common histopathologic denominator. Based on this observation, we suggest the term "widespread congenital dermal nevus with large nodules" to be the most appropriate for this rare, but distinctive, type of congenital nevus.     

Expanding the clinicopathologic spectrum of palisaded encapsulated neuroma

Palisaded encapsulated neuroma (PEN; solitary circumscribed neuroma) is a benign, morphologically characteristic cutaneous or mucosal neuroma. Most are solitary lesions on the face, neck or oral mucosa. Histologically, the majority appears as dermal nodules of Schwann cell-rich fascicles, with or without distinctive encapsulation. To further expand on the existing literature regarding this neuroma, we herein describe three PENs with unique clinical and histopathologic features. All occurred on the acral skin, a rarely described site. Furthermore, one exceptional patient presented with multiple PEN on the bilateral hands, biopsies of which showed a prominent plexiform architecture. Awareness that PEN may occur on acral skin, may rarely present as multiple lesions, and recognition of the plexiform variant is important because PEN may histologically mimic other peripheral nerve sheath tumors. Additionally, misdiagnosis may have significant clinical implications.     

Pedunculated Nodules as a Variant of Dermatofibrosarcoma Protuberans

Dermatofibrosarcoma protuberans (DFSP) is a rare disease of dermal fibroblastic origin that accounts for less than 5% of all soft tissue sarcomas in adults. DFSP grows slowly and is an asymptomatic lesion at the initial diagnosis. Herein, we report a case of multiple pedunculated nodules as a variant of DFSP. A 47-year-old man presented with a 7-month history of multiple well-circumscribed, firm, pedunculated nodules on the inguinal area. Histopathologic examination results showed densely packed uniform spindle cells with a storiform and cartwheel pattern, and positivity for CD34. Wide excision and skin graft were performed and at the 6-month follow-up, there was no evidence of recurrence or metastasis.     

Digital verrucous fibroangioma: a new variant of verrucous hemangioma.

In this article, we report on 4 cases of a dome-shaped nodule on the dorsum of the finger, which had been present since birth and slowly enlarged. On light microscopic examination, these nodules showed similarities to verrucous hemangioma. However, they were characterized by distinct clinical features and proliferation of dermal connective tissue. We consider these tumors to be a variant of verrucous hemangioma and propose to term them digital verrucous fibroangioma.     

Fibrous papule of the nose

SUMMARY.— A study has been made of 34 cases of fibrous papule of the nose presenting at St John's Hospital for Diseases of the Skin in the past decade, Histological sections from biopsies of these lesions were examined and compared with lesions of juvenile melanoma and naevus cell naevus arising on the face. In 2 patients fibrous papules were investigated by enzyme histochemical methods. Fibrous papules were usually single small nodules on the nose, often simulating angiomata, moles or pyogenic granulomata. The sexes were equally affected and most of the patients were in the third to the fifth decades. Although these lesions were not distinctive clinically, histologically they presented a characteristic appearance, which included a distinctive fibro-vascular component composed of broad bands of connective tissue orientated at right angles to the surface and interspersed with multinucleate cells and undoubted naevus cells, and an increased number of epidermal clear cells. A marked decrease in the elastic staining properties of the dermal connective tissue was characteristic of these lesions as was increased staining with P.A.S. The available evidence, including the enzyme histochemical findings, is consistent with this lesion being a member of the naevus cell spectrum of disorders.     

Atypical fibrous histiocytoma of the skin and subcutis in childhood and adolescence

The authors have observed 15 examples of a distinctive fibrohistiocytic lesion in children and adolescents which they chose to designate as "atypical fibrous histiocytoma" (AFH). Patient ages ranged from 1 to 19 years (mean 9.3 yr.). Only two cases were encountered in the first year of life, but 7 were seen in children under the age of 10 yr. The anatomic distribution of AFH showed a tendency for a truncal origin (66%), and none was located in the skin of the face, neck, or scalp. Tumor sizes ranged from 1 to 3 cm, and one-third were 2 cm or greater in maximum dimension. Histologically, AFH was characterized by a multinodular, dermal or dermal-subcuticular proliferation of spindle cells, with tapered, cytologically bland nuclei. However, nucleocytoplasmic ratios were increased when compared with those of normal fibroblasts. Nuclear chromatin was dispersed or vesicular; nucleoli were seen in a minority of cases, but mitotic activity was regularly present. Admixed giant cells were present but infrequent, cellularity was dense, and a storiform growth pattern was consistently seen. Mean followup in this group of cases averaged 75 mo. Seven patients (47%) had tumor recurrences after initial excision; in two of these, tissue margins had been free of involvement. The authors conclude that AFH of childhood is analogous to a lesion that has previously been reported as "benign fibrous histiocytoma" in adults. Complete excision and regular postoperative surveillance are recommended for these tumors.     

Rhabdomyosarcoma presenting as a cutaneous nodule

Two patients with rhabdomyosarcoma presented clinically with dermal nodules on the face. The first patient was a 12-month-old girl with a 2 X 3-cm-diameter red nodule on her left cheek that had begun as a small red papule when she was 3 months old and had progressively increased in size. The second patient was a 19-year-old girl who presented with an enlarging mass on her right cheek that had begun as a pea-sized nodule three months previously. In both cases, biopsies revealed a rhabdomyosarcoma in the underlying soft tissue with extension into the overlying dermis. Rhabdomyosarcoma presenting as a dermal nodule is rare. It usually presents as an asymptomatic papule without distinctive clinical features and therefore may result in delayed diagnosis unless a biopsy is performed.     

Subcutaneous T-cell lymphoma: A clinical, histopathologic, and immunohistochemical study of six cases

Recently, T-cell lymphoma localized to the subcutaneous tissue has been reported. We report the clinical, histolpgic, immunohistochemical, and molecular genetic findings in 6 patients who we believe had this peculiar T-cell lymphoma with its unique morphologic and clinical features. All patients presented with deep-seated nodules, most frequently on the extremities, and with systemic complaints of low-grade fever, fatigue, myalgias, and weight loss. In all cases, the neoplastic lymphocytic infiltrate was confined to the subcutaneous tissue, predominantly in a lobular pattern. Hemorrhage, necrosis, and rare erythrophagocytosis were also seen. Immunohistochemical staining was predominantly T-cell reactive (CD43, CD3, and CD45RO). Clonal rearrangements of the β and γ chains of the T-cell antigen receptor genes were found in 1 case. Three of the 6 patients died within 22 months of the diagnosis of lymphoma. We believe that subcutaneous T-cell lymphomas are a distinctive group of peripheral T-cell lymphomas with unusual clinical and morphologic features and that they should be distinguished from other types of lymphoma.     

Lipidized fibrous histiocytoma: clinicopathologic analysis of 22 cases

We report the clinicopathologic analysis of 23 tumors from 22 patients with lipidized fibrous histiocytoma (FH), which has been an underrecognized variant of cutaneous FH. The 16 men and 6 women patients (male/female ratio, 2.7:1) ranged in age from 21 to 82 years (median, 50 years). The location of the tumor was concentrated strikingly in the lower limb, especially around the ankle, hence the alternative informal designation of "ankle-type" FH. The tumors showed relatively large size compared with those of conventional FH, ranging up to 8 cm in greatest dimension (median, 2.5 cm), and tended to be polypoid and yellowish in color. Hyperlipidemia was only a rare and perhaps incidental association in two cases. Histologically, lipidized FH was characterized by accumulation of numerous foam cells, smaller numbers of siderophages, and stromal hyalinization typically appearing "wiry," keloidlike, or osteoidlike, although focal features of ordinary FH almost always coexisted and were identified as a focal storiform or curlicue pattern of spindle tumor cells, epidermal hyperplasia, and peripheral "entrapped" dermal collagen. Although follow-up data are limited, the prognosis appears to be good with no recurrence, even after incomplete excision. These clinicopathologic features highlight lipidized FH as a distinctive variant, which can be distinguished from ordinary or other variants of FH, as well as from other foam cell-rich cutaneous lesions, especially xanthoma.     

The cutaneous pathology of Cowden''s disease: new findings

Histological, histochemical and immunohistochemical findings were studied in 40 cutaneous biopsies from 7 patients with Cowden's disease. Most facial biopsies showed a spectrum of trichilemmomas and related follicular malformations, including cylindrical trichilemmomas, lobulate trichilemmomas (14 lesions), and a keratinizing type sharing features with inverted follicular keratosis. One facial growth showed trichilemmomal changes without apparent follicular origin. Studies for common papilloma virus structural antigens were negative, apart from a typical common wart in one patient. Immunohistochemical studies in 6 facial trichilemmomas and acral keratoses, using a panel of anti-keratin antibodies, disclosed only abnormal differentiation with lack of large keratins in the lobulate trichilemmomas. Nine biopsies revealed a distinctive type of fibroma characterized by an organized pattern of interwoven fascicles of collagen bundles with a laminated or tortuous appearance, embedded in abundant mucin. A number of fibromas showed striking hyalinization; these may represent a second microscopic hallmark of Cowden's disease in addition to facial trichilemmomas.     

The spectrum of benign dermal dendritic melanocytic proliferations

Dermal melanocytoses (DMs) comprise a heterogeneous group of benign lesions, located on skin and mucous membranes, characterized by dendritic melanocytes in the dermis. Although they share common histopathological features, some variants may present only as bluish or grey patches, some only as papules/nodules/plaques and others may show combination of all of these lesions. Despite the fact that blue naevus (BN) is typically characterized with papulonodular lesions, its variants may show all of the aforementioned presentations. Mongolian spot, naevus of Ota and naevus of Ito are patchy DMs distinguished by their specific localizations. Apart from these classical forms, many atypical variants without unique clinicopathological characteristics have been described in the literature making the nomenclature of DMs more complicated. However, congenital dermal melanocytosis and acquired dermal melanocytosis seem to be crucial umbrella terms that encompass all patchy DMs in atypical locations. Papules or subcutaneous nodules on patchy lesions and association of epidermal pigmentation presenting as brownish patches may be encountered as rare features of DMs. On the other hand, delayed‐onset subcutaneous nodules may be typical presentations of melanoma in patchy DMs; therefore, they deserve special attention. Large plaque‐type BN with subcutaneous cellular nodules is a newly described entity, harbouring clinical features of various DMs together and has a high risk of melanoma. The whole spectrum of dermal dendritic melanocytic proliferations is discussed including novelties and controversial issues.     

Cutaneous mycobacterial spindle cell pseudotumor: a potential mimic of soft tissue neoplasms

A 55-year-old man with scleroderma treated with prednisone and etanercept presented with enlarging sporotrichoid nodules on the forearm. Microscopically, there were large circumscribed dermal and subcutaneous nodules of spindled and epithelioid cells, resembling a spindle cell neoplasm. Small foci of neutrophils were also present, and a subsequent Ziehl-Neelsen stain highlighted beaded acid-fast bacilli in the interstitium. Tissue culture demonstrated Mycobacterium chelonae. Cutaneous mycobacterial spindle cell pseudotumor is an exceedingly rare lesion, with only 6 previously reported cases. Although these included patients with autoimmune disease receiving immunosuppressive therapy, this is the first case reported in association with a tumor necrosis factor alpha inhibitor, etanercept. Furthermore, this represents the first mycobacterial spindle cell pseudotumor described in association with M. chelonae. Mycobacterial spindle cell pseudotumor should be considered in the differential diagnosis of cutaneous spindle cell proliferations, especially in immunocompromised patients.     

Acral subcutaneous steatocystoma multiplex: A distinct subtype of the disease?

Steatocystoma multiplex (SM) is a hamartomatous malformation of the pilosebaceous duct consisting of dermal cysts filled with a sebum‐like material. SM lesions are typically located in areas with sebaceous follicles, although atypical presentations involving sites lacking sebaceous follicles have exceptionally been described. We reviewed retrospectively a series of 32 histologically diagnosed SM observed in our department in the period 2006–2010, evaluating the kinds of lesions and their locations, and family history of SM and associated disorders, to focus on the clinical features of the acral subcutaneous variety of SM and to estimate its prevalence. We found five patients (four women and one man) with asymptomatic deep, skin‐colored nodules on the flexor surfaces of distal upper extremities with a mean age at diagnosis and at disease onset of 32.5 and 26 years, respectively. The prevalence was 15%. All five cases were sporadic. The male patient had eruptive syringomas as an associated condition, together with a family history of this tumour. Acral subcutaneous SM may represent a distinct disease variety by virtue of its distinctive clinical features. Dermatologists should be aware of this form, which has to be included in the wide panel of diseases involving subcutaneous tissue.     

Vitiligo vs. hypopigmented mycosis fungoides (histopathological and immunohistochemical study, univariate analysis)

Vitiligo is a common skin disease characterized by the presence of well circumscribed, depigmented milky white macules devoid of identifiable melanocytes. On the other hand, hypopigmented mycosis fungoides (MF) is a rare variant of MF which presents clinically as persistent hypopigmented macules and patches. Both disorders show a predominance of CD8+ T cells in tissue samples and hence the differentiation between the two diseases on clinical, histopathological and even immunohistochemical grounds may offer great difficulty. The aim of this work is to identity certain histopathological clues which might help to differentiate between the two diseases. The study included 54 patients (26 vitiligo patients and 28 patients with Hypopigmented MF). Skin biopsies were taken and examined by hematoxylin and eosin and CD3, CD4 and CD8 markers were performed for ten vitiligo and nine MF patients. We have found that epidermotropism, hydropic degeneration of basal cells, partial loss of pigment, preservation of some melanocytes, presence of lymphocytes within the papillary dermis, increased density of the dermal infiltrate and wiry fibrosis of the papillary dermal collagen were detected with a significantly higher incidence in hypopigmented MF rather than vitiligo (P-values < 0.0001, < 0.00011, < 0.00011, = 0.001, = 0.008 and = 0.001 respectively). On the other hand, focal thickening of the basement membrane, complete loss of pigmentation, total absence of melanocytes, as well as absence or sparsness of lymphocytes in the dermal papillae were seen much more frequently in vitiligo. Statistical analysis of these differences was significant with P-values < 0.00011, < 0.00011, < 0.00011, = 0.008 respectively, regarding these pathological criteria. We conclude that differentiation of hypopigmented MF from vitiligo is possible by relying on the histopathological clues described in this study. This is particularly useful in areas of the world where cost benefit is crucial.     

The Morphological Variations of Fibrous Histiocytomas

The morphological variants of dermal fibrous histiocytomas have engendered a confusing terminology. One hundred and eighty-nine cases of fibrous histiocytomas were studied in order to define the morphological spectrum exhibited by these lesions.
Based on the prevailing morphological components, fibrocollagenous, vascular, or histiocytie. an arbitrary division into three main categories was made. A fourth group was defined to include those cases in which a fully developed storiform pattern was the dominant morphological feature. The majority (115 cases) of the lesions were of the fibrocollagenous variety. Lesions with an angiomatous component (vascular variety) were the next most common (41 cases). Thirteen of the tumors were of the histiocytic variety.
Twenty tumors were of the storiform variety and fulfilled many of the microscopic criteria of dermatofibrosarcoma protuberans. This latter group often presents a diagnostic problem and may stimulate fibrosarcoma, aggressive fibromatosis or other connective tissue neoplasias. The combination of several clinical and pathological features are helpful in better separating this variety from the more benign forms.
The presence of different well-defined morphological components developing in the same tumors suggests a common origin.     

The cutaneous pathology of facial lesions in Cowden''s disease

A study of 11 facial lesions from 7 patients with Cowden's disease indicated that most belong to a spectrum of related follicular malformations. The most distinctive lesions included multiple facial trichilemmomas, which were frequently cylindrical, resembling a blown-up hair follicle, but could be lobular. Four of the 5 trichilemmomal lesions were from the centrofacial area. Three periauricular lesions showed the pattern of tumor of follicular infundibulum without trichilemmonal features. Two lesions were epidermal without a follicular component and resembled digitate warts. No evidence of virus infection was found using an antiserum to papilloma virus.