Mycosis fungoides is an epidermotropic primary cutaneous T-cell lymphoma, represented com-posed of small and medium-sized lymphocytes with cerebriform nuclei. Differential diagnosis of cutaneous T-cell lymphoma and chronic autoimmune dermatoses, including psoriasis, may present significant chal-lenges in some cases. We analyzed three clinical cases of mycosis fungoides, in which psoriasis was initially diagnosed. Histological and immunohistochemical studies with a wide panel of antibodies (CD4 CD8, CD2, CD5, CD7, CD3) were performed, and monoclonal T-lymphocyte populations were determined with PCR. We propose an algorithm for diagnosing mycosis fungoides. Keywords: mycosis fungoides, psoriasis, morphology, immunohistochemistrycal study, diagnosis

A clinical case of leprosy diagnosis in a citizen of the Republic of Chad (lepra-endemic region), а 24 year old male, student is presented. In 2019 the patient received permission to stay in the Russian Federation for educational purposes, entered one of the federal universities, and studied in Moscow, living in a hostel. During these years, he applied to various clinics, complaining of skin rashes and other symptoms characteristic of leprosy, without the effect of the prescribed treatment. In 2023, after contacting the clinic of skin diseases of the I.M. Sechenov First Moscow State Medical University (Sechenov University), was first sent to the The Federal State Research Center of Dermatovenereology and Cosmetology of the Ministry of Health of Russia with suspicion of leprosy. The results of clinical and laboratory studies including bacterioscopic examination of skin scarifications and pathohistological study of the skin confirmed the diagnosis: A30.5 Leprosy, multibacterial form, lepromatous type, active stage. This case presentation testifies to the lack of alertness regarding leprosy, especially among doctors conducting medical examinations of foreign citizens in order to obtain permission to stay in the Russian Federation, which may cause the spread of dangerous infectious diseases on the territory of the Russian Federation.

Kaposi’s sarcoma is a systemic tumor multifocal disease of vascular genesis. In the classic Kaposi’s sarcoma, lesions are most often localized on the skin of the lower extremities, lesions of the mucous membranes are extremely rare. The article presents a rare clinical case of the classic Kaposi’s sarcoma in a 56 years old man with lesions of the oral mucosa. This clinical case is of particular interest due to the difficulties of differential diagnosis of Kaposi’s sarcoma and lichen planus when mucous membranes are involved in the pathological process. The presented case emphasizes the importance of a histological examination of the biopsy in differential diagnosis of Kaposi’s sarcoma. In case when the rash is widespread and the mucous membranes are involved, it is recommended to collect the material from the skin, because the histological picture will be more characteristic. It is important to pay attention to the duration of the elements’ existence, as morphological diagnosis in the early stages of Kaposi’s sarcoma can imitate the pattern of chronic dermatosis.

Androgenetic alopecia is a genetically determined, multifactorial disorder characterized by the miniaturization of terminal hair into pathologically thinned vellus hair, eventually leading to hair loss. Minoxidil and 5α-reductase inhibitors are considered first-line treatments for androgenetic alopecia; however, some patients experience adverse effects or show inadequate response to these therapies, necessitating the development of novel, effective, and safe treatment options. Exosomes are small membrane-bound vesicles involved in intercellular communication. They can carry proteins, lipids, RNA, and growth factors that may promote prolongation of the anagen phase (growth phase), enhance microcirculation, and stimulate hair follicle regeneration. This article presents two clinical cases of patients with mild to moderate androgenetic alopecia treated with a solution containing exosomes derived from salmon tissue. Phototrichogram data demonstrated a marked therapeutic benefit in both cases, including increased hair density (via higher anagen hair count) and reduced vellus hair proportion (from 21/12% to 10/8% and from 32/10% to 3/10% before and after treatment, respectively).

BACKGROUND: The most common diagnosis given to patients with chronic urticarial rashes is chronic spontaneous urticaria (prevalence in the population is 0.1–1.4%). However, similar symptoms can also be observed in other rarer diseases: urticarial vasculitis, hypocomplementemic urticarial vasculitis syndrome, cryopyrine-associated syndromes and Schnitzler's syndrome. AIM: to analyze the clinical features and histological characteristics of skin biopsies in patients with chronic urticarial rashes to optimize the management and improve differential diagnosis. MATERIALS AND METHODS: At a retrospective stage, 9 patients with chronic urticarial rashes and a histological examination were selected from the archival data of the Clinic of Skin and venereal fiseases named after V.A. Rakhmanov Sechenov University from January 2019 to April 2022. Prospective patient recruitment was from January 2022 to September 2023 and included 11 patients who underwent skin biopsy. Data obtained from the analysis of demographic characteristics are presented as median and interquartile range. Histological parameters were assessed by qualitative and quantitative methods. RESULTS: The study included 20 patients (16 women and 4 men) aged 23 to 63 years, 36.5. Depending on the clinical and histological characteristics, the patients were divided into three groups: 9 patients with chronic spontaneous urticaria, disease duration from 2 to 132 months, 24 months [18; 33]; 9 patients were diagnosed with urticarial vasculitis, the duration ranged from 7 to 180 months, 30 [24; 84]. There were 2 patients diagnosed with hypocomplementemic urticarial vasculitis syndrome; the duration of the disease was 24 months. Clinically, chronic spontaneous urticaria was distinguished by a shorter duration of the disease and a shorter duration of existence of individual elements. Standard or increased doses of antihistamines were effective in five patients with chronic spontaneous urticaria. In addition, patients with chronic spontaneous urticaria also had atypical signs of rashes, which indicates a transition group between chronic spontaneous urticaria and urticarial vasculitis. In patients with urticarial vasculitis and hypocomplementemic urticarial vasculitis syndrome, clinical features such as longer duration of blistering, burning and soreness, residual hyperpigmentation, and resistance to antihistamine therapy were more often observed. When conducting a histological examination, the main histological features for urticarial vasculitis were leukocytoclasia, fibrin deposits and damage to the vascular walls with fibrin deposition; fibrinoid necrosis was rarely visualized, which, in combination with the above features, was present in only two patients with hypocomplementemic urticarial vasculitis syndrome. CONCLUSION: This study presents the results of our own observations, analysis of the clinical and histological characteristics of patients with various diseases (chronic spontaneous urticaria, urticarial vasculitis, hypocomplementemic urticarial vasculitis syndrome). The results obtained may be useful for optimizing the differential diagnosis of diseases accompanied by urticarial rashes.

Introduction. Mycosis fungoides is challenging to diagnose in its early stages due to its resemblance to benign dermatoses like atopic dermatitis and parapsoriasis. Current diagnostic methods are often insufficient. The aim was to evaluate the diagnostic significance of cell adhesion molecule 1 (CADM1) and psoriasin (S100A7) markers for the differential diagnosis of these diseases. Materials and methods. A retrospective immunohistochemical study of skin biopsies from 45 patients was conducted using antibodies to CADM1 and psoriasin. The study material consisted of 6-mm incisional skin biopsies from 15 patients with mycosis fungoides, 15 with atopic dermatitis, and 15 with parapsoriasis. All diagnoses were verified histologically and immunophenotypically (for mycosis fungoides). The results were evaluated by calculating the percentage of positively stained cells using QuPath v0.5.1 software. Results. A statistically significant difference in CADM1 expression was found between mycosis fungoides and parapsoriasis. In mycosis fungoides, CADM1 expression averaged 60% (range 50–90%), while in parapsoriasis it did not exceed 20% or was absent. Psoriasin expression was equally high (>80%) in both mycosis fungoides and atopic dermatitis, with no significant differences. Conclusion. CADM1 is a highly informative marker for differentiating mycosis fungoides from parapsoriasis, whereas psoriasin demonstrated no differential value between mycosis fungoides and atopic dermatitis. CADM1 shows promise for inclusion in diagnostic algorithms for early-stage mycosis fungoides. Keywords: mycosis fungoides, atopic dermatitis, parapsoriasis, differential diagnosis, immunohistochemistry, CADM1, psoriasin