Francisco Jimenez

Frontal fibrosing alopecia versus lichen planopilaris: a clinicopathological study.

Background  Frontal fibrosing alopecia (FFA) is an acquired scarring alopecia currently considered a clinical variant of lichen planopilaris (LPP). Our purpose was to examine the clinicopathological features of FFA. In addition, we investigated the similarities and differences between FFA and LPP.

The immunohistochemical expression of CD34 in human hair follicles: a comparative study with the bulge marker CK15

Background.  Anti‐CD34 antibodies label the bulge region of mouse hair follicles. However, in human hair follicles, CD34 immunoreactivity is found in the outer root sheath below the bulge zone. The immunohistochemical staining of CD34 in catagen and telogen follicles has not been evaluated.

Human recombinant stem-cell factor induces melanocytic hyperplasia in susceptible patients☆

BACKGROUND Recombinant human stem-cell factor (SCF), a cytokine acting on hematopoietic progenitor cells, has potential for the treatment of several hematologic and oncologic disorders. In a hematology-oncology phase I trial of SCF, several patients had cutaneous hyperpigmentation at the SCF subcutaneous injection sites. OBJECTIVE Our purpose was to investigate the pathogenesis of this hyperpigmentation phenomenon. METHODS Skin biopsy specimens were obtained before, at the completion of, and after SCF therapy and were processed for histology, immunohistology, and electron microscopy. RESULTS Skin at the site of SCF injection had an increased number of melanocytes, increased melanocytic dendrite extension, and melanin as compared with noninjected tissue. Immunohistochemical stains revealed an increase in staining with melanocyte-specific monoclonal antibodies HMB-45 and NKI/beteb, and a monoclonal antibody to the receptor for SCF, c-kit. CONCLUSION Subcutaneous injection of SCF results in hyperplasia of melanocytes. SCF may be useful in the treatment of melanocytopenic disorders, but caution may be necessary in patients with disorders of melanocyte proliferation.

Human epithelial hair follicle stem cells and their progeny: current state of knowledge, the widening gap in translational research and future challenges.

Epithelial hair follicle stem cells (eHFSCs) are required to generate, maintain and renew the continuously cycling hair follicle (HF), supply cells that produce the keratinized hair shaft and aid in the reepithelialization of injured skin. Therefore, their study is biologically and clinically important, from alopecia to carcinogenesis and regenerative medicine. However, human eHFSCs remain ill defined compared to their murine counterparts, and it is unclear which murine eHFSC markers really apply to the human HF. We address this by reviewing current concepts on human eHFSC biology, their immediate progeny and their molecular markers, focusing on Keratin 15 and 19, CD200, CD34, PHLDA1, and EpCAM/Ber‐EP4. After delineating how human eHFSCs may be selectively targeted experimentally, we close by defining as yet unmet key challenges in human eHFSC research. The ultimate goal is to transfer emerging concepts from murine epithelial stem cell biology to human HF physiology and pathology.

Lymphoepithelioma-like carcinoma of the skin treated with Mohs micrographic surgery in combination with immune staining for cytokeratins

Lymphoepithelioma-like carcinoma of the skin (LLCS) is a rare cutaneous neoplasm that histologically resembles nasopharyngeal lymphoepithelioma. Conventional surgical excision carries a considerable rate of recurrence (three of 11 reported cases with such treatment, with one patient dying of metastatic disease). We report the first case of lymphoepithelioma-like carcinoma of the skin treated with Mohs micrographic surgery. Because of its tendency to occur on the face and its potential for recurrence after incomplete removal, this tumor is a good candidate for treatment with Mohs micrographic surgery. Immunohistochemical staining of frozen sections for cytokeratins may help to detect neoplastic cells that may be obscured by the dense lymphoplasmacytic infiltrate associated with this tumor.

Morphometric Analysis of the Human Scalp Hair Follicle: Practical Implications for the Hair Transplant Surgeon and Hair Regeneration Studies

BACKGROUND The bulge stem cell region is a structure important for the regeneration of the pilosebaceous unit. Measurements of the different compartments of a hair follicle may have implications in hair transplantation and hair regeneration studies. OBJECTIVE To measure the length of the different portions of the occipital scalp hair and to estimate at what depth they are located. METHODS AND MATERIAL Hair follicles from the occipital scalp were obtained from 29 individuals. Measurements were performed on digital pictures using a software imaging system. Antibody anticytokeratin (CK), 15 was used as a bulge stem cell marker. RESULTS The mean length of a scalp hair follicle is 4.16 mm. The infundibulum measures 0.76 mm, the isthmus 0.89 mm, and the inferior portion 2.5 mm. The insertion of the arrector pili muscle is located 1.65 mm deep. CK15 immunoreactivity starts at a depth of 1 mm and extends down to 1.8 mm. CONCLUSION The ideal depth for the trichophytic procedure is to cut the wound edge at a depth of less than 1 mm to avoid the bulge zone. The data provided can serve as an objective anatomical reference in hair regeneration studies using horizontally transected follicles. The authors have indicated no significant interest with commercial supporters.

A pilot clinical study of hair grafting in chronic leg ulcers

Epidermal sheets spread centrifugally postinjury from the hair follicle infundibulum to reepithelialize the wound bed. Healing progresses faster in skin areas rich in terminal hair follicles. These observations are consistent with the role of the hair follicle as a major reservoir for progenitor cells. To evaluate the feasibility and potential healing capacity of autologous scalp follicular grafts transplanted into the wound bed of chronic leg ulcers, 10 patients with ulcers of an average 36.8 cm2 size and a 10.5‐year duration were included in this pilot study. Within each ulcer we randomly assigned a 2 × 2 cm “experimental” square to receive 20 hair grafts and a nongrafted “control” square of equal size. The procedure seemed to be safe, although major unrelated complications occurred in two patients. At the 18‐week end point, we observed a 27.1% ulcer area reduction in the experimental square as compared with 6.5% in the control square (p = 0.046) with a maximum 33.5% vs. 9.7% reduction at week 4 (p = 0.007). Histological analyses showed enhanced epithelialization, neovascularization, and dermal reorganization. We conclude that terminal hair follicle grafting into wound beds is feasible in an outpatient setting and represents a promising therapeutic alternative for nonhealing chronic leg ulcers.

Reflections on how wound healing-promoting effects of the hair follicle can be translated into clinical practice

Clinicians have long reported that hair‐bearing areas tend to heal more rapidly than those lacking hair follicles. In the past decade, numerous scientific studies have corroborated clinical evidence, showing a direct nexus between the human hair follicle and the wound healing process. The migration of epithelial follicular stem cells to the skin surface to help in the wound re‐epithelialization and the effect of the hair cycle on the wound healing rate underline the influence of the hair follicle in the healing process. In clinical practice, non‐healing wounds are pathologies of high prevalence with significant associated burden costs for the healthcare system. As the population ages, the prevalence of this pathology is expected to increase in future years. The recent advances in understanding the biology of hair follicle stem cells have created the challenges of using this newly acquired knowledge in practical therapeutic applications. Chronic leg ulcers are an example of the targeted pathologies that urgently need better therapies. In this essay, our aim is to raise interest in this question, reviewing what is known in relation to the connections between hair follicles and wound healing, and elaborating on future directions that the field might take, including implications for clinical practice.

Template Stamps to Estimate Recipient Site Density in Hair Transplantation

There are two ways to prepare the recipient sites that will hold follicular unit grafts: premade sites, in which the surgeon prepares all of the sites before graft insertion, and the “stick and place” technique, in which the sites and grafts are made and placed one at a time. Irrespective of the technique that the surgeon uses, there is no reliable method of preparing the sites that ensures homogenous distribution and consistent density of the incisions in the recipient zone. The surgeon usually relies on experience and good visual technique. Because of the importance, and the difficulty, of creating the sites at a specific density, we have developed a simple but objective method based on the use of “stamp templates,” which are painted onto the patient’s scalp skin before making the incisions.

Frontal Fibrosing Alopecia: A disease fascinating for the researcher, disappointing for the clinician and distressing for the patient.

K E Y W O R D S cicatricial alopecia, frontal fibrosing alopecia, hair, hair transplantation, scarring alopecia Mediteknia Hair Transplant Clinic and Medical Pathology Group, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain Salford Royal NHS Foundation Trust, The University of Manchester, Salford, Manchester, UK Department of Pathology, Hospital General Universitario Reina Sofía y Universidad de Murcia, Murcia, Spain