Genome-wide association study in frontal fibrosing alopecia identifies four susceptibility loci including HLA-B*07:02.

Frontal fibrosing alopecia (FFA) is a recently described inflammatory and scarring type of hair loss affecting almost exclusively women. Despite a dramatic recent increase in incidence the aetiopathogenesis of FFA remains unknown. We undertake genome-wide association studies in females from a UK cohort, comprising 844 cases and 3,760 controls, a Spanish cohort of 172 cases and 385 controls, and perform statistical meta-analysis. We observe genome-wide significant association with FFA at four genomic loci: 2p22.2, 6p21.1, 8q24.22 and 15q2.1. Within the 6p21.1 locus, fine-mapping indicates that the association is driven by the HLA-B*07:02 allele. At 2p22.1, we implicate a putative causal missense variant in CYP1B1, encoding the homonymous xenobiotic- and hormone-processing enzyme. Transcriptomic analysis of affected scalp tissue highlights overrepresentation of transcripts encoding components of innate and adaptive immune response pathways. These findings provide insight into disease pathogenesis and characterise FFA as a genetically predisposed immuno-inflammatory disorder driven by HLA-B*07:02.

Folliculitis decalvans: Effectiveness of therapies and prognostic factors in a multicenter series of 60 patients with long-term follow-up.

BACKGROUND: Folliculitis decalvans (FD) is a rare neutrophilic cicatricial alopecia that poses a therapeutic challenge. OBJECTIVES: To describe the therapeutic response in a large number of cases of FD with long-term follow-up and analyze potential prognostic factors associated with severity of form and with a better therapeutic response. METHODS: This multicenter prospective study included patients with FD who had a minimum of 5 years of follow-up. Severity was assessed by the maximum diameter of the cicatricial area. Therapeutic response was evaluated according to stabilization of the size of the cicatricial areas and the improvement in clinical symptoms. RESULTS: A total of 60 patients (37 men [61.7%] and 23 women [38.3%]) with a mean age of 40 years were included. Earlier age of onset (P = .01) was statistically associated with severity of form. Treatment with rifampicin and clindamycin, tetracyclines, and intralesional steroids was the most effective. No statistically significant prognostic factors predicting a better therapeutic response were found. LIMITATIONS: Because FD is a rare disease, the main limitation was the sample size. CONCLUSIONS: An earlier age of onset was associated with the severe form of the disease. The proposed specific therapeutic protocol can be a very useful tool in clinical dermatologic practice.

Drug-induced systemic lupus erythematosus in a child after 3 years of treatment with carbamazepine.

Drug-induced lupus erythematosus (DILE) is a less severe variant of systemic lupus erythematosus (SLE) that generally resolves within weeks or months after the withdrawal of the implicated drug. DILE is unusual during childhood, with the most frequent age of presentation being at 50-70 years of age. Among different drugs, most commonly procainamide and hydralazine have been implicated as a cause of DILE. However carbamazepine (CBZ) is considered a low-risk drug and very few cases have been reported in children. We describe the case of CBZ-induced SLE in a 9-year-old girl following 3 years of CBZ therapy. This case report shows that drug-induced SLE is an important side-effect to be considered, even after long-term treatment with CBZ, and also during childhood.

Primary Signet-Ring Cell/Histiocytoid Carcinoma of the Eyelid: A "Binocle" Presentation of the "Monocle Tumor".

Primary cutaneous signet-ring cell carcinoma is a rare and aggressive neoplasm which diffusely involves dermis and subcutis of the eyelid or axillae. Neoplastic cells show a signet-ring cell or histiocytoid morphology in variable number, and can be found intermingled among collagen bundles, sparing the epidermis. This neoplasm typically appears in the eyelids of elderly men, in the form of a painless infiltration and swelling but with no other specific clinical feature, and frequently causes diagnostic retardation and worse prognosis. Frequent involvement of both eyelids of the same eye has given it the name of monocle tumor. Only 29 cases have been described in English literature to date, of which 7 developed metastases, mainly on regional lymph nodes. The authors present a case of involvement of contralateral eyelid, which has only been described previously in 2 cases. The immunohistochemical profile of the involvement in the contralateral eye, and the absence of other metastasis, suggest that it is locally spread from the initial lesion. However the possibility of being a second primary tumor or metastasis cannot be readily ruled out.

Eritema nudoso / Erythema nodosum

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Primitive follicular induction in molluscum contagiosum.

BACKGROUND: Molluscum contagiosum (MC) is the commonest human poxvirus infection. Follicular induction has rarely been observed in the epidermis surrounding lesions of MC. A virus-induced localized proliferation of germinative/stem cells of the folliculosebaceous-apocrine unit has been suggested as the underlying cause, however few reports of this peculiar phenomenon exist in the literature and the mechanisms involved in this proliferation require further study. METHODS: We prospectively collected MC cases showing multifocal areas of primitive follicular induction involving the adjacent undersurface epidermis. Immunohistochemical expression of BerEP4, PHLDA1 and cytokeratin 20 (CK20) was evaluated in the basaloid germs surrounding the lesions. For PHLDA1, we used epidermal melanocytes as a positive internal control. For BerEP4, we employed a basal cell carcinoma (BCC) and for CK20, colon as positive external controls. An incubation without the primary antibody functioned as an external negative control. RESULTS: All the cases studied showed an intense positive staining of the basaloid buds with BerEP4 and weaker stain for PHLDA1. CK20 showed the presence of scattered Merkel cells within the induced epidermal basaloid proliferations favoring their reactive origin. DISCUSSION: The pathogenetic mechanisms behind the development of these microscopic features and the link between follicular induction and poxvirus infection are explored. Awareness of this unusual phenomenon by dermatopathologists will be helpful in avoiding a misdiagnosis of a superficial BCC in such cases. CONCLUSIONS: BerEP4 and PHLDA1 were consistently expressed in the areas of primitive follicular induction surrounding lesions of MC. CK 20 stained the Merkel cells present in the basaloid buds. All these findings support the reactive origin of this phenomenon, which we believe is most probably viral-induced.

"Apocrine Hidrocystoma and Cystadenoma"-like Tumor of the Digits or Toes: A Potential Diagnostic Pitfall of Digital Papillary Adenocarcinoma.

Digital papillary carcinoma (DPC) is a rare, underreported, and often misdiagnosed malignant tumor of the sweat glands. It is often located on the digits and toes and most commonly occurs in male individuals in their fifties to seventies. Because of lack of pain, slow growth, and an inconspicuous appearance, clinical diagnosis is often missed or delayed. In contrast, apocrine hidrocystoma (AH) is a cystic adenoma that arises from the apocrine secretory coil, and it is extremely rare for AHs to develop on the digits. We report 7 cases of DPC, including clinical course, histopathologic and immunohistochemical findings, and therapeutic approach in which the initial histopathologic diagnosis in all cases was AH or cystadenoma. However, complete excision of the neoplasms led to a final diagnosis of DPC. After an adequate treatment, no recurrence or metastasis was found in any of the cases described. All the cases studied showed similar histopathologic and immunohistochemical findings. The initial incisional biopsy showed large unilocular or multilocular cystic spaces situated within the dermis, lined by a double layer of epithelial cells with tiny papillary structures. No cellular atypia, necrosis, or pleomorphism was observed. However, complete excision revealed neoplastic lesions involving the dermis and/or subcutis, with an infiltrative pattern and papillary projections into luminal spaces. Immunoperoxidase studies showed positivity for CK7, S-100 protein, CEA, p63, smooth muscle actin, and calponin. DPC is a rare but life-threatening malignancy, therefore it is important to be able to identify such a lesion both clinically and histopathologically, treat it, and monitor the patient for the tumor's potential recurrence and metastasis. Pathologists and dermatopathologists should be aware that a histopathologic diagnosis of AH or cystadenoma on the fingers and toes should be established with caution, because probably those lesions represent the superficial and cystic component of an underlying DPC, and a wider excision should be performed.

Foreign Body Granulomas.

A large list of foreign substances may penetrate the skin and induce a foreign body granulomatous reaction. These particles can enter the skin by voluntary reasons or be caused by accidental inclusion of external substances secondary to cutaneous trauma. In these cases, foreign body granulomas are formed around such disparate substances as starch, cactus bristles, wood splinters, suture material, pencil lead, artificial hair, or insect mouthparts. The purpose of this article is to update dermatologists, pathologists, and other physicians on the most recent etiopathogenesis, clinical presentations, systemic associations, evaluation, and evidence-based management concerning foreign body granulomatous reactions of skin.

Nodular amyloidosis at the sites of insulin injections.

Amyloid is characterized by its fibrillary ultrastructure, and more than 20 proteins have been described to date as possible precursors. Among them, insulin and enfuvirtide represent the only medications described as amyloidogenic substances. We describe two diabetic patients, who were undergoing long-standing subcutaneous insulin treatment, who developed subcutaneous nodules at the sites of insulin injections. Histopathologic examination showed the presence of eosinophilic and amorphous masses in deep dermis, which stained positive with Congo red, amyloid P substance and anti-human insulin antibody. Whether the type of injected insulin played a role or not in the pathogenesis of the process is still uncertain, because all described patients used both fast-acting and slow-acting insulins at the same injection sites. Our second case showed nodular insulin-derived amyloid tumors only at the sites where exclusively fast-acting insulin was injected, which supports the notion that fast-acting insulin may also be the cause of this disorder. Insulin-derived nodular amyloidosis is probably underdiagnosed because of the small body of literature in comparison with the prevalence of insulin dependent diabetic patients. This underdiagnosis probably is because of its clinical similarity with the lesions of lipohypertrophy at the sites of insulin injections, which is rarely biopsied.

Dermatofibrosarcoma Protuberans of the Vulva With Myoid Differentiation.

Dermatofibrosarcoma protuberans (DFSP) is an uncommon soft-tissue tumor characterized by a relatively high risk for local recurrence and low risk for metastasis. Many histopathologic variants of DFSP have been described, including the fibrosarcomatous and myoid variants, which may obscure the diagnosis in some cases, especially when arising in unusual locations. Of all the variants described so far, the only one with prognostic relevance is the FS-DFSP variant, which implies tumor progression and a higher possibility for metastasis. The authors report a case of a giant DFSP, located on the vulvar area, which histopathologically showed areas of fibrosarcomatous and myoid differentiation, and discuss the importance of the myoid variant in regards of the debated histogenesis of DFSP.

Sebocyte-like cell primary cutaneous melanoma: a rare cytologic variant of malignant melanoma.

Although rising incidence rates of cutaneous melanoma have been observed during the last 4 decades in white populations worldwide, the sebocyte-like cell variant has been described only twice in the literature to date. In our case, a 64-year-old man presented for evaluation of a changing pigmented lesion on the left upper back. Excision of the lesion revealed an invasive melanoma with a Breslow depth of 3.3 mm. Microscopic sections showed a predominantly dermal-based tumor composed of sheets and nests of enlarged epithelioid melanocytes, most of which showed an uncommon phenotype with multivacuolated cytoplasms and scalloped nuclei, features that gave them a strong resemblance to mature sebocytes. The lesional cells expressed S100 protein, Melan-A, and p16, whereas adipophilin was positive only within the sebocyte-like component of the neoplasm and showed focal nonspecific staining. The patient's sentinel lymph node biopsy was positive for micrometastases, although a subsequent position emission tomography scan was unremarkable. Sebocyte-like melanocytes are a rare distinctive type of melanocytes that can be found mostly in benign but also in malignant melanocytic lesions. They usually present focally within the lesions and, therefore, do not represent a diagnostic problem in nevus or primary cutaneous melanoma. However, when sebocyte-like melanocytes are the main cellular component of a melanocytic lesion or when they are found in the context of metastatic melanoma, they may create a potential diagnostic pitfall; for this reason, awareness of this cell type is important.

Cutaneous epithelioid hemangioendothelioma on the sole of a child.

Epithelioid hemangioendothelioma (EHE) has been considered to be a low-grade malignant vascular neoplasm, although follow-up of recent series has demonstrated that EHE involving the skin and soft tissues should be better regarded as a fully malignant vascular tumor since it has more metastatic potential than previously thought. We report a case of an EHE involving the left sole of 6-year-old boy, the youngest patient with cutaneous EHE described to date. Immunohistochemical studies demonstrated a lymphatic endothelial line of differentiation for neoplastic cells. Cutaneous EHE is rare in childhood, with only five previously described cases.

Merkel cell carcinoma arising within a poroma: report of two cases.

Merkel cell carcinoma (MCC) has been reported in association with other types of cutaneous neoplasms within the same lesion, including squamous cell carcinoma, Bowen's disease, actinic keratosis, follicular cysts, trichoblastoma and lentigo maligna, among others. However, the association of MCC and sweat gland tumors has never been described in the literature. We report two unique cases of MCC that developed within cutaneous poromas. A 56-year-old male (Patient 1) and an 81-year-old female (Patient 2) presented with nodules on the upper arm and lower back, respectively. Histopathologic study of both cases revealed a tumor in the dermis composed of poroid and cuticular cells intermingled with a proliferation of small round cells that showed characteristic histopathological and immunohistochemical features of MCC. In both cases, the two neoplasms were tightly admixed and distinct, suggesting that the MCC could have developed within a previously existing poroma. No morphological features of transition between the two tumors were seen. Neoplastic cells of MCC expressed immunoreactivity for chromogranin, synaptophysin, neuron-specific enolase, CAM 5.2 and cytokeratin 20, the last two markers showing the characteristic paranuclear dot-like pattern. In contrast, the poroma cells only expressed cytokeratin MNF116. Metastatic deposits were not identified in the regional lymph nodes or distantly.

Immunohistochemistry in the diagnosis of cutaneous bacterial infections.

The identification of pathogens is of vital importance for the adequate treatment of infections. During the past 2 decades, the approach to histopathologic diagnosis has been dramatically transformed by immunohistochemistry (IHC) specifically in the diagnosis and classification of tumors and more recently in the diagnosis of infectious diseases in tissue samples. The main goals of this article were to: (1) identify by IHC the cutaneous structures where bacterial pathogens are expressed in the course of infection, (2) identify the specific cells in which bacterial pathogens are expressed in positive cases, and (3) describe the pattern of distribution of the bacterial antigens within these cells (nuclear, cytoplasmatic, or membranous). This article is an up-to-date overview of the potential uses and limitations of IHC in the histopathologic diagnosis of cutaneous bacterial infections. In conclusion, IHC is especially useful in the identification of microorganisms that are present in low numbers, stain poorly, are fastidious to grow, culture is not possible, or exhibit an atypical morphology.

Immunohistochemistry in the diagnosis of cutaneous viral infections- part II: cutaneous viral infections by parvoviruses, poxviruses, paramyxoviridae, picornaviridae, retroviruses and filoviruses.

BACKGROUND: Cutaneous viral infections are increasing in recent years, particularly in immunocompromised patients. OBJECTIVE: Immunohistochemistry (IHC) provides a rapid and helpful tool that can be applied to confirm the diagnosis of specific viral infections that may be difficult to diagnose with certainty using routine microscopy alone. METHODS: Several immunostains that are useful in histopathology have been reviewed and tested in cutaneous samples of viral infections. Emphasis is placed on new stains and novel uses of existing stains. RESULTS: This article is an up-to-date overview of the potential uses of IHC in the histopathologic diagnosis of cutaneous viral infections by parvoviruses, polyomaviruses, poxviruses, paramyxoviridae, picornaviridae, retroviruses, and filoviruses. LIMITATIONS: Specific monoclonal antibodies are commercially available only for some members of these virus families. CONCLUSIONS: IHC may assist dermatopathologists to appropriately diagnose viral infections by parvoviruses, polyomaviruses, poxviruses, paramyxoviridae, picornaviridae, retroviruses, and filoviruses.