Dermatopathology

A clinical risk is an inherent risk in healthcare processes, including skin biopsy procedures, and may lead to misdiagnoses, increased healthcare costs and potential harm to patients. Indeed, clinical and histopathological data must be integrated if we are to reduce clinical risks and improve diagnostic accuracy in the diagnosis of dermatologic diseases. Although dermopathology services used to be part of a dermatologist’s duty, the recent centralization of these laboratories has caused a loss of expertise and increased both complexity and safety issues. Some countries have implemented clinical-pathological correlation programs aimed at facilitating communication between clinicians and dermatopathologists. However, Italy has regulatory and cultural barriers that make the implementation of these programs difficult. Therefore, an internal analysis was carried out to assess the efficacy and impact that skin biopsy procedures for inflammatory and neoplastic conditions have on the quality of care in our dermatology department. As the analysis evidenced a high number of descriptive pathologic reports and discordant diagnoses, a multidisciplinary group of four dermatologists, four general pathologists and one dermatopathologist was set up. Herein, we present the results of this analysis and project and describe the structure of the multidisciplinary group. We also discuss the pros and cons, possibilities and limitations of our project, including the regulatory barriers of the Italian National Health System. Full article

Kissing nevus is a congenital melanocytic neoplasm arising in those parts of the body that split at some point during embryological development (i.e., eyelid; penis), resulting in two adjacent melanocytic nevi. To date, 23 cases of kissing nevus of the penis have been described, and dermatoscopic and histological findings are available in 4/23 cases. We report a dermatoscopic, histological and confocal microscopic analysis in a new case of the kissing nevus of the penis in a 57 years old man. Dermatoscopic analysis showed large globules in the central area and a peripheral pigment network; the histological examination confirmed the presence of an intradermal melanocytic nevus with minimal junctional component and congenital features. Moreover, we reported, for the first time, confocal microscopy findings in the kissing nevus of the penis, revealing the presence of dendritic cells in correspondence with the epidermis and suggesting a state of cellular activity. Considering the clinicopathological features of the lesion, a conservative approach was adopted, and a clinical follow-up was planned after six months. Full article

Spiny keratoderma (SK) was first described by Brown in 1871 and is characterized by numerous 1–2 mm spines of keratin on the palms and soles, usually sparing the dorsal surfaces, or disseminated over the trunk. Histologically, the “spine” represents a column of hyperkeratosis. Several different forms are known, including familial, sporadic, post-inflammatory and paraneoplastic. Although an association of SK with melanoma has been reported, the significance of such co-occurrence remains unclear due to the limited number of cases. To increase the body of knowledge and shed further light on this rare condition, we present a case of SK in a patient with a recent history of melanoma in situ. Full article

Fungal folliculitis (including tinea capitis and Majocchi granuloma) has a wide range of clinical presentations, and biopsy may be obtained to distinguish this from other conditions with similar presentations. The study aims to evaluate the proportion of hairs infected in biopsies of fungal folliculitis. Copath records were searched for diagnoses of fungal folliculitis, tinea capitis and Majocchi granuloma between 1 January 2000 and 31 December 2020. Confirmed cases were pulled and reviewed by a dermatopathologist to count the total number of hairs on the sample and the total infected. Of 72 included cases, the median number of hair follicles per biopsy was 3 (IQR 1,4), and the median proportion of hairs infected was 54.2% (IQR 33.3%, 100.0%). Nineteen (26.4%) had only one hair included in the biopsy which was also an infected hair (100% of hairs were infected). The percentage of total hair follicles infected differed significantly depending upon location (p = 0.0443), with a smaller percentage of infected hairs in biopsies of tinea capitis. Clinicians should be cautious when using biopsy for diagnosis of fungal folliculitis, specifically, when there are few hairs in the specimen. Failure to capture infected hairs leads to false negative diagnoses. Full article

Basal cell carcinoma (BCC) is the most common cutaneous malignancy, usually occurring in sun-exposed areas. Although BCC in the scrotal region is uncommon, it carries a higher risk of metastasis than BCC at other sites. Here, we report two cases of BCC that developed in the scrotal region: Case 1 presented as a superficial nodule and Case 2 as a subcutaneous nodule. Histopathologically, both tumors lacked continuity with the surface epidermis and formed an intradermal nodule. In Case 1, BCC occurred for the first time and presumably developed de novo. Case 2 underwent excision of a scrotal BCC 5 years previously, and the histopathological diagnosis at that time was nodular BCC. However, when the original specimen was re-examined, it was determined that, although the tumor had been completely resected, part of the lesion had moved away from the nodular area to represent a micronodular phenotype, an aggressive BCC subtype. We hypothesized that partial evolution from a nodular to a micronodular phenotype may have contributed to the recurrence of BCC in Case 2. Full article

Traditionally, the term melanoma in situ (MIS) is used to designate a horizontal (radial) growth phase of malignant melanoma (MM) in which there is no histological evidence of any invasion (or microinvasion) of neoplastic melanocytic cells into the superficial or papillary dermis. In daily dermatopathological practice, we are faced with misleading definitions, such as “melanoma in situ with regression,” which risk affecting homogeneity for comparison purposes of pathological reports of malignant melanoma. The authors conducted a literature review using PubMed and Web of Science (WoS) as the main databases and using the following keywords: “Malignant Melanoma in situ” or “Melanoma in situ” and “regression” and/or “radial growth phase regression.” A total of 213 articles from both analyzed databases were retrieved; finally, only eight articles in English were considered suitable for the chosen inclusion criteria. In consideration of the absence of studies with large case series, of reviews with meta-analyses, and, therefore, of a broad scientific consensus, expressions including “melanoma in situ with regression” should be avoided in the histopathological report. Instead, they should be replaced with clearer and more exhaustive definitions. Full article

Cutaneous epithelioid angiomatous nodule is a rare benign vascular tumour of the skin with characteristic microscopic features, of which 65 cases have so far been reported after the initial description of this entity in 2004. We present here a new typical case of this rare lesion and provide a comprehensive review of all the previously published cases, delineating the salient clinicopathological features of this rare tumour. Full article

A novel type of cell underwent identification between 2005 and 2008 and was denominated the “telocyte” in 2010. In 2012, transmission electron microscopy revealed the presence of telocytes in the dermis. The aim of the present study was to report important changes in immunostained CD34 cells following the treatment of lower limb lymphedema using a specific lymphatic therapy technique. A clinical trial involving the evaluation of changes in immunostained CD34 cells in the epidermis and dermis (10 randomly selected histological fields) of a patient before and after intensive treatment for clinical stage II lymphedema was conducted using the Godoy Method, which was adapted to the treatment of skin fibrosis. The evaluation involved the use of the Weibel multi-point morphometric method. Comparisons were performed using the t-test with a 95% significance level. An important increase in CD34 cells was found with redistribution occurring following treatment. The treatment of primary lymphedema of the lower limbs resulted in the clinical reversal of fibrosis and an increase in the number of immunomarked CD34 cells. Full article

Granuloma annulare (GA) is a benign, self-limiting granulomatous inflammatory disease that exhibits different histologic patterns. Infrequently, granuloma annulare can be associated with malignancy, the so-called malignancy-associated granuloma annulare (MGA). In this study, we aimed to compare the clinical and histopathological differences between GA and MGA. We retrospectively reviewed patient charts and identified 35 patients diagnosed with GA and concurrent hematological or solid organ malignancies as a case group. Additionally, we identified 33 patients without any known solid organ or hematological malignancy as a control group. MGA is commonly seen in the seventh decade of life, while GA affects the younger population. MGA is most commonly presented in the extremities of the body. The most common malignancy associated with MGA was chronic lymphocytic leukemia. Prostate cancer was the most common type of solid organ malignancy that was associated with MGA. The most common histopathological pattern seen in MGA was interstitial, comprising half of the cases. Multinucleated giant cells were present in half of the MGA cases and in most of the control group. In the literature, there are no established features that distinguish MGA from GA. Although MGA and GA have overlapping features, in our series, we found that the interstitial pattern was more common in MGA, while the necrobiotic pattern was more common in GA. Full article

Year after year, the incidence and prevalence rates of cutaneous Malignant Melanoma (MM) show a continuous increase and, according to the most up-to-date American Cancer Society (ACS) projections, it is estimated that 97,610 new melanomas will be diagnosed in 2023 (about 58,120 in men and 39,490 in women) and approximately 7990 people are expected to die of melanoma (about 5420 men and 2570 women) [...] Full article

Post-pemphigus acanthomas have been rarely discussed in the literature. A prior case series identified 47 cases of pemphigus vulgaris and 5 cases of pemphigus foliaceus, out of which 13 developed acanthomata as a part of the healing process. Additionally, a case report by Ohashi et al. reported similar recalcitrant lesions on the trunk of a patient with pemphigus foliaceus being treated with prednisolone, IVIG, plasma exchange, and cyclosporine. Some view post-pemphigus acanthomas as variants of hypertrophic pemphigus vulgaris, being difficult to diagnose when they present as only single lesions, with a clinical differential of an inflamed seborrheic keratosis or squamous cell carcinoma. Here, we present a case of a 52-year-old female with a history of pemphigus vulgaris and four months of only topical therapy (fluocinonide 0.05%) who presented with a painful, hyperkeratotic plaque on the right mid-back that was found to be a post-pemphigus acanthoma. Full article

Neoplasms of sweat glands and the breast may be morphologically and immunophenotypically similar. A recent study showed that TRPS1 staining is a highly sensitive and specific marker for breast carcinoma. In this study, we analyzed TRPS1 expression in a spectrum of cutaneous sweat gland tumors. We stained five microcystic adnexal carcinomas (MACs), three eccrine adenocarcinomas, two syringoid eccrine carcinomas, four hidradenocarcinomas, six porocarcinomas, one eccrine carcinoma-NOS, 11 hidradenomas, nine poromas, seven cylindromas, three spiradenomas, and 10 syringomas with TRPS1 antibodies. All of the MACs and syringomas were negative. Every cylindroma and two of the three spiradenomas demonstrated intense staining in cells lining the ductular spaces, with negative to relatively weak expression in surrounding cells. Of the 16 remaining malignant entities, 13 were intermediate to high positive, one was low positive, and two were negative. From the 20 hidradenomas and poromas, intermediate to high positivity was revealed in 14 cases, low positivity in three cases, and negative staining in three cases. Our study demonstrates a very high (86%) expression of TRPS1 in malignant and benign adnexal tumors that are mainly composed of islands or nodules with polygonal cells, e.g., hidradenomas. On the other hand, tumors with small ducts or strands of cells, such as MACs, appear to be completely negative. This differential staining among types of sweat gland tumors may represent either differential cells of origin or divergent differentiation and has the potential to be used as a diagnostic tool in the future. Full article

Mucous membrane pemphigoid (MMP), also known as cicatricial pemphigoid (CP), is a heterogeneous group of subepidermal blistering diseases that affect the mucous membranes, most frequently in the eye and oral cavity. MMP is often unrecognized or misdiagnosed in its early stages due to its rarity and nonspecific presentation. We present the case of a 69-year-old female in which MMP of the vulva was not initially suspected. The first biopsy, from lesional tissue for routine histology, revealed fibrosis, late-stage granulation tissue, and nonspecific findings. A second biopsy, from perilesional tissue for direct immunofluorescence (DIF), revealed DIF findings typical of MMP. Scrutiny of both the first and second biopsies revealed a subtle but telling histologic feature: subepithelial clefts along adnexae in the context of a scarring process with neutrophils and eosinophils, which can be an important clue to MMP. This histologic clue has been previously described; reinforcing its importance may prove useful for future cases, especially those for which DIF is not feasible. Our case demonstrates the protean presentations of MMP, the need for persistence in sampling unusual cases, and the relevance of inconspicuous histologic features. The report highlights this underrecognized yet potentially decisive histologic clue to MMP, reviews current biopsy guidelines when MMP is suspected, and delineates the clinical and morphological features of vulvar MMP. Full article

Dermatofibrosarcoma protuberans (DFSP) is a dermal malignant mesenchymal tumor. Most variants are associated with a high risk of local recurrence and a low risk of metastasis. The classic histomorphology of this tumor is made up of uniform, spindle-shaped cells, arranged in a storiform pattern. Tumor cells characteristically infiltrate the underlying subcutis in a honeycomb pattern. Less common variants of DFSP have been identified: myxoid, pigmented, myoid, granular cell, sclerosing, atrophic, and fibrosarcomatous. Only the fibrosarcomatous variant has been shown to differ significantly from classic DFSP in terms of clinical outcome; fibrosarcomatous DFSP has been shown to be associated with a greater risk of local recurrence and metastatic potential than classic DFSP. However, the other variants may pose diagnostic difficulty as they resemble other types of spindle cell neoplasms, especially in small biopsy specimens. This article reviews the clinical, histologic, and molecular features of DFSP variants, as well as possible pitfalls in their diagnosis and how to resolve them. Full article

Hyperkeratosis lenticularis perstans, also known as Flegel’s disease (FD), is a rare cutaneous disorder affecting mainly the lower extremities of middle-aged people. Due to its rarity, this disease is usually not recognized by physicians resulting in a delay in diagnosis, especially in those cases with atypical cutaneous involvement. Herein, we present a 72-year-old woman who developed FD characterized by a generalized distribution, involving, in addition to the lower limbs, the trunk and the upper limbs as well. We performed a description of the dermoscopic and pathologic features of this rare entity, also carrying out a brief reappraisal of the cases of FD with a diffuse, atypical and generalized distribution that have been described in the literature. Histopathology with clinical correlation is the cornerstone of the diagnosis, even and especially in atypical cases. This patient with a disease duration of 58 years also represents the longest-lasting case of FD reported in the literature. Full article