Telogen effluvium: a 360 degree review.

Telogen effluvium (TE) is one of the most common presentations of diffuse non-cicatricial alopecia and is generally self-limited. Multiple causes are associated with TE onset and its maintenance, with stress being felt the most common factor. The multifactorial etiologies involved in TE makes it a complex disorder to diagnose and treat often placing this entity into a "waste basket" diagnosis. By critically assessing the available scientific literature we aimed to review the multifaceted aspects of TE. Our objectives were to review the pathogenesis with the role of stress (including Coronavirus 19-associated TE), as well as to describe the main clinical findings, its differential diagnosis and the current knowledge on TE treatments along with the future treatment's insights.

ROS1 Fusion Angiomatoid Spitz Nevus With Eccrine Duct Fibroadenomatosis and Syringoid Features.

ABSTRACT: Eccrine duct fibroadenomatosis is a reactive histological phenomenon observed in a variety of inflammatory and neoplastic pathologies. We report a case of a ROS1 fusion angiomatoid Spitz nevus with associated acrosyringeal hyperplasia and a syringoma-like ductal proliferation in a young female patient.

Patterns of Mucin Deposition in Lichen Planopilaris: A Journey From Follicular "Bubbles" to Perifollicular Fibroplasia.

ABSTRACT: Lichen Planopiolaris (LPP) is a scarring alopecia characterised by a perifollicular lymphoid cell infiltrate at the level of the infundibulum and isthmus. While perifollicular mucinous fibroplasia is an established finding in LPP, intrafollicular mucin deposition has not been previously reported. We describe two cases with this histopathology and suggest it may represent a helpful clue to the diagnosis of LPP, in the appropriate clinical setting.

The role of hair follicle counts and ratios in the histopathological assessment of androgenic alopecia, alopecia areata and telogen effluvium: does counting 'count'?

The histopathological assessment of scalp biopsies for the diagnosis of alopecia is most commonly undertaken in specialist centers. Occasionally, pathologists encounter such specimens outside a specialist setting or at a low frequency, which makes a confident diagnosis difficult. A methodical approach is essential to identify and interpret the histopathological findings, and one of the diagnostic tools is the use of follicular counts and ratios. This method is particularly emphasized in the context of non-scarring alopecia and, furthermore, for the identification of alopecias with overlapping features. We raised the question as to what is the role of follicular hair counts and ratios in the differential diagnosis of non-scarring alopecia with overlapping features, and sought the answer in our literature review. The English literature on the histopathological assessment of horizontal scalp biopsies taken for the evaluation of non-scarring alopecia, focusing on hair follicle counting as a diagnostic tool, with particular emphasis on androgenetic alopecia, alopecia areata, and telogen effluvium, was reviewed. Follicular counts and ratios are a helpful diagnostic tool. However, these need to be coupled with the morphological features specific for each alopecia subtype to render a confident diagnosis.

Loss of CD34 Expression within an Interstitial Dermal Lymphoid Cell Infiltrate Is a Helpful Clue to the Diagnosis of Morphea.

A dermal interstitial lymphocytic infiltrate may represent a diagnostic challenge, particularly if the clinical history is not provided. We present three cases within the histological spectrum of morphea in which the immunohistochemical marker CD34 was helpful in confirming the diagnosis.

Dermal Cystine Crystals: An Incidental Finding During Mohs Surgery.

ABSTRACT: Cystinosis is an autosomal recessive lysosomal storage disorder with intracellular cystine accumulation caused by mutations in the CTNS gene. We present a case of a 48-year-old woman with a history of cystinosis and squamous cell carcinoma treated with Mohs micrographic surgery where widespread deposition of cystine crystals were noted on frozen sections of the Mohs layers. These were rectangular to polygonal refractile crystals within the cytoplasm of dermal fibroblasts and macrophages which were highlighted by polarized light microscopy. This case illustrates the use of frozen section processing to demonstrate the presence of intracellular cystine crystals. Moreover, because patients with cystinosis may be predisposed to developing carcinomas postrenal transplantation, Mohs surgeons should be aware of this unusual phenomenon when evaluating the slides.

Dataset for the Reporting of Merkel Cell Carcinoma: Recommendations From the International Collaboration on Cancer Reporting (ICCR).

Accurate and complete pathology reports are critical for the optimal management of cancer patients. Protocols for the pathologic reporting of Merkel cell carcinoma (MCC) have been developed independently by the Royal College of Pathologists (UK) and the College of American Pathologists. In this study, data elements for pathologic reporting of MCC were analyzed by an international panel of pathologists and clinicians with the aim of developing a common, internationally agreed upon dataset useful for clinical practice. The International Collaboration on Cancer Reporting expert review panel developed a protocol containing "core" (required) and "noncore" (recommended) elements. Core elements were defined as those that had evidentiary support and were unanimously agreed upon by the review panel as essential for the clinical management, staging, and/or assessment of prognosis in patients with MCC. Noncore elements were those considered to be clinical of interest, but with lesser degrees of supportive evidence or nonactionable implications. Ten core data elements for pathology reports on primary MCC were defined. Development and agreement on this evidence-based protocol at an international level was accomplished in a timely and efficient manner. The template developed for melanoma reporting was used as a structural base for this initiative. It is applicable to, and may facilitate the development of, protocols for other tumor types. Widespread utilization of an internationally agreed upon structured pathology dataset for MCC can be expected to lead to improved patient management. It should also facilitate collaborative clinical research.

Diagnostic Accuracy of Trichoscopy in Trichotillomania: A Systematic Review.

Trichotillomania is formally classified as a mental health disorder, but it is commonly diagnosed by dermatologists. The aim of this systematic review is to assess the diagnostic value of trichoscopy in diagnosing trichotillomania. The analysis identified the 7 most specific trichoscopic features in trichotillomania. These features had the following prevalence and specificity: trichoptilosis (57.5%; 73/127 and 97.5%, respectively), v-sign (50.4%; 63/125 and 99%), hook hairs (43.1%; 28/65 and 100%), flame hairs (37.1%; 52/140 and 96.5%), coiled hairs (36.8%; 46/125 and 99.6%), tulip hairs (36.4%; 28/77 and 89.6%), and hair powder (35.6%; 42/118 and 97.9%). The 2 most common, but least specific, features were broken hairs and black dots. In conclusion, trichoscopy is a reliable new diagnostic method for hair loss caused by hair pulling. Trichoscopy should be included as a standard procedure in the differential diagnosis of trichotillomania in clinical practice.

Dermatofibrosarcoma protuberans (DFSP) in children: A combined multidisciplinary approach.

Dermatofibrosarcoma protuberans (DFSP) is rare, comprising (1%-6%) of all sarcomas. The incidence is less than one per million before the age of 20. It is a locally aggressive tumor with a low risk of metastasis. We share our experience in the management of three pediatric patients with complex cases of DFSP in a combined surgical approach involving plastic and dermatologic surgery, using the slow Mohs micrographic surgery technique.

Melanocytic and pseudomelanocytic nests coexist in interface dermatitis from head-neck sun-exposed skin: A report of three cases.

Discrete junctional cellular aggregates ("nests"), partially staining with melanocytic markers, are described in lichenoid tissue reaction, mainly from chronically sun-exposed skin. The concomitant epidermal flattening and papillary dermal fibrosis with melanophages, may raise the differential diagnosis to that of a regressing melanoma. We describe three cases of interface dermatitis of the head/neck area with clinicopathological features of melanotic discoid lupus erythematosus. These cases showed junctional aggregates, a few composed of inflammatory cells and colloid bodies ("pseudomelanocytic nests"), while others composed of S100- but MART-1+, MITF+, and SOX-10+ cells ("true melanocytic nests"); negativity of the melanocytic component for PRAME was a clue to benignity. True junctional melanocytic nesting may be induced by lichenoid dermatoses on chronically sun-damaged skin. The presence of colloid bodies and of the double negativity for S100 (within nests) and PRAME (both within nests and single melanocytes), together with clinicopathological correlation, avoids misdiagnosis.

Dramatic response of metastatic cutaneous angiosarcoma to an immune checkpoint inhibitor in a patient with xeroderma pigmentosum: whole-genome sequencing aids treatment decision in end-stage disease.

"Mutational signatures" are patterns of mutations that report DNA damage and subsequent repair processes that have occurred. Whole-genome sequencing (WGS) can provide additional information to standard diagnostic techniques and can identify therapeutic targets. A 32-yr-old male with xeroderma pigmentosum developed metastatic angiosarcoma that was unresponsive to three lines of conventional sarcoma therapies. WGS was performed on his primary cancer revealing a hypermutated tumor, including clonal ultraviolet radiation-induced mutational patterns (Signature 7) and subclonal signatures of mutated DNA polymerase epsilon (POLE) (Signature 10). These signatures are associated with response to immune checkpoint blockade. Immunohistochemistry confirmed high PD-L1 expression in metastatic deposits. The anti-PD-1 monoclonal antibody pembrolizumab was commenced off-label given the POLE mutation and high mutational load. After four cycles, there was a significant reduction in his disease with almost complete resolution of the metastatic deposits. This case highlights the importance of WGS in the analysis, interpretation, and treatment of cancers. We anticipate that as WGS becomes integral to the cancer diagnostic pathway, treatments will be stratified to the individual based on their unique genomic and/or transcriptomic profile, enhancing classical approaches of histologically driven treatment decisions.

Tiger-like mycosis fungoides: an unusual clinical presentation of a rare variant of mycosis fungoides.

Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma. Mycosis fungoides classically presents in the skin as patches, plaques, tumors, or erythroderma, progressing to involve the lymph nodes and peripheral blood. The many clinical variants, with different histologic patterns, and the subtle early clinical and histologic changes may delay early diagnosis and present a diagnostic challenge for clinicians. The greatest challenge in diagnosis is the pre-mycotic stage, which may closely resemble eczematous or psoriasiform dermatitis clinically and histologically. The persistence of lesions and inadequate response to treatment are the first warning signs. Later stages of MF have a poor prognosis with poor therapeutic response and fatal outcome. We describe a 72-year-old man, who presented with a two-year history of an unusual eruption, which started on the abdomen, around the waistline, and gradually spread to involve his back, trunk, and buttocks. Clinically, the skin eruption presented as tiger-like stripes. The diagnosis was confirmed after histopathologic examination. The patient was treated with NB-UVB phototherapy with marked improvement.

Lichen planus and lichenoid dermatoses: Conventional and emerging therapeutic strategies.

Having reviewed the diverse clinical subtypes of lichenoid disease and the postulated molecular basis thereof in the first article in this 2-part continuing medical education series, we discuss herein the existing and emerging treatment strategies in the most common clinical forms of lichenoid inflammation and provide an overview of their pharmacodynamics and evidence base. The scope of this review is not to exhaustively discuss treatment modalities for all lichenoid variants discussed in the previous article of this series. Instead, the focus will be on frequently encountered subtypes of lichen planus and on linking mechanisms of disease with mechanisms of drug action. Future directions and potential avenues for translational research will also be discussed.

Lichen planus and lichenoid dermatoses: Clinical overview and molecular basis.

Deriving from the Greek word λειχήν for "tree moss" and the Latin word planus for "planar," lichen planus is a relatively uncommon and heterogeneous cutaneous disorder that typically develops in middle-aged adults. Despite the significant clinical burden associated with the disorder, little well-conducted molecular research has been undertaken, possibly because of heterogeneity impeding consistent and confident phenotyping. The multiple variants of lichenoid disease bear overlapping clinical and pathologic features despite manifesting as distinct clinical disorders. The first article in this 2-part continuing medical education series provides a comprehensive overview of the clinical and pathologic characteristics of cutaneous lichenoid dermatoses and links these manifestations to recent advances in our understanding of the underlying pathobiology of such diseases.