Collision Lesions: Genuine Collision (Conflict) or not?

By definition, the term "collision lesion" refers to two or more tumors coinciding in the same anatomic position or visceral organ. Collision lesions coexisting on the same skin location are defined as collision skin lesions (CSLs). Although this term implies a conflict between the tumors, this is not the case. CSLs appear to be rare, but still pose a significant diagnostic problem in everyday clinical practice and clinicians should be aware of their existence. The aim of this study was to elucidate the problem of CSLs in clinical practice, with an emphasis on classification of CSLs according to position dependence, tumor histogenesis, etiology, and possible lesion combinations in CSLs, as well as diagnostic possibilities. According to our results, accurate clinical diagnosis could be only rarely reached, requiring lesion excision and pathohistological confirmation of CSLs. Considering the fact that tumors in CSLs can be partially or completely overlying or can even be positioned one within the other, the existence of two or more tumors is extremely difficult to detect.

Cytotoxic T lymphocytes as a potential brake of keratinocyte proliferation in psoriasis.

Psoriasis is a chronic papulosquamous skin disease, histologically characterized by epidermal hyperproliferation and dermal infiltration of inflammatory cells. The majority of T lymphocytes infiltrating dermis are CD4+ T lymphocytes secreting type 1 and type 17 cytokines. These cytokines are responsible for triggering keratinocyte proliferation as well as chemokine secretion and subsequent migration of other inflammatory cells in the skin. Contrarily, lymphocytes that accumulate in epidermis are mainly CD8+ T lymphocytes. According to the recent findings, these cells can also secrete type 1 and type 17 cytokines. However, it is demonstrated so far that epidermal CD8+ T lymphocytes contain higher amounts of cytolytic molecules, such as perforin, granzyme B and granulysin whose role in psoriasis pathogenesis is still unknown. Therefore, in this article we hypothesize the active involvement of cell mediated cytotoxicity in killing the proliferating keratinocytes as a mechanism of potential self-defense and possible brake in psoriatic plaque formation, maintaining skin homeostasis.

[Guidelines for the diagnosis and treatment of psoriasis]. / Smjernice za dijagnostiku i lijecenje vulgarne psorijaze.

Croatian dermatovenerological society of the Croatian Medical Association formed the working group which consists of leading experts for psoriasis in Croatia. After a critical analysis of relevant scientific papers, the working group has developed guidelines for the diagnosis and treatment of psoriasis.

Negative and positive life experiences in patients with psoriatic arthritis.

Recent data suggest that childhood and adulthood stressors may play a significant role in the development of an autoimmune disease. The present study explores the relationship between psoriatic arthritis (PsA) and positive and negative life events during childhood and adulthood in psoriatic patients. Forty-five patients with psoriatic arthritis and 101 controls (patients with skin conditions considered to be "non-psychosomatic") were enrolled in the study. All participants completed a specific questionnaire measuring traumatic life experiences [Traumatic Antecedents Questionnaire (TAQ)]. The TAQ assesses positive personal experiences (competence and safety) and negative personal experiences (neglect, separation, secrets, emotional, physical and sexual abuse, trauma witnessing, other traumas and exposure to alcohol/drugs) from early childhood to adulthood. The patients with psoriatic arthritis exhibited lower mean scores of total positive experiences during late childhood (latency) as compared to the control group. Negative experiences during four developmental periods appeared more frequently in patients with psoriatic arthritis than in the controls. The most frequently reported negative experiences were neglect, emotional abuse, physical abuse, sexual abuse, alcohol/drug abuse and other traumas. The present findings add evidence to the relationship between retrospectively reported childhood experiences and psoriatic arthritis. Furthermore, a high amount of reported emotional and physical abuse occurs in patients with psoriatic arthritis during latency and adolescence.

Childhood and adulthood traumatic experiences in patients with psoriasis.

It is well known that several psychiatric disorders may be related to childhood psychological trauma. Recent studies have associated childhood exposure to trauma to some skin diseases. Our study aimed at exploring whether psoriasis is related to the reported positive and negative traumatic life events in different age intervals beginning from early childhood to adulthood. Furthermore, we investigated differences between psoriatics with early and late onset according to traumatic experiences in different age intervals. Also, we investigated the possible correlation of traumatic experiences with the disease severity. One hundred patients with psoriasis and 101 controls (patients with skin conditions considered to be "non-psychosomatic") were enrolled in the study. All participants completed a specific questionnaire measuring traumatic life experiences (Traumatic Antecedents Questionnaire, TAQ). The TAQ assesses positive personal experiences (competence and safety) and negative personal experiences (neglect, separation, secrets, emotional, physical and sexual abuse, trauma witnessing, other traumas and exposure to alcohol/drugs) from early childhood to adulthood. The severity of psoriasis was estimated according to the Psoriasis Area and Severity Index (PASI), a standardized measuring instrument. The amount of positive experiences did not differ significantly among groups, except for safety scores that were higher in controls compared with both psoriatic groups (early and late onset). On the other side, negative traumatic experiences appeared more frequently in patients with psoriasis during all developmental periods. We found no correlation between severity of psoriasis and traumatic experiences. The present study demonstrates an increased history of childhood and adulthood negative traumatic experiences in patients with psoriasis compared to the control group. Our findings suggest a relationship between retrospectively reported negative traumatic experiences and psoriasis.

[Treatment of alopecia areata: modern principles and perspectives]. / Lijecenje alopecije areate: suvremeni principi i perspektive.

Alopecia areata (AA) is a frequent disease with nonscarring hair loss on the scalp and/or body. Hair follicle in alopecia areata is not irreversibly destroyed, so potential for hair regrowth remains. Considering unknown etiopathogenesis, treatment of AA is symptomatic and directed toward halting disease activity. Lymphocytic inflammatory infiltrate around hair follicle, increased levels of autoantibodies, cytokine abnormalities and increased prevalence of autoimmune comorbidities, support the hypothesis of AA as an organ-specific autoimmune disorder. Therefore, investigations are directed toward new immunomodulatory or immunosuppressive drugs with induction effect on hair growth. New biologic drugs and their influence on hair growth as well as genetic therapy for alopecia areata are currently under investigation. Contemporary principles in therapy of alopecia areata and treatments available will be discussed in this article.

Molecular and genetic mechanisms in melanoma.

Recent studies have indicated an increasing incidence of melanoma worldwide. Although UV signature mutations are found rarely in melanoma cells, there is some evidence that intense intermittent exposure to sunlight can induce melanocyte tumorigenesis, and this is also observed after UV irradiation in some animals. The purpose of this paper is to review some of the most important mechanisms involved in the pathogenesis of this tumor. Genetic studies showed the familiar melanoma is linked to the mutation or deletion of the suppressor gene CDKN2A, and perhaps to CDK4. Studies showed that BRAF mutation is frequent in primary and metastatic melanoma cells but also in naevocytic nevi. This mutation activates the RAF/MEK pathway. Exposure to UV radiation induces immunosuppression. Recent investigations showed that chemokines, angiogenesis, metalloproteinases can play a role in the mechanism of metastasis. In spite of these advances the initiating events are still not completely understood. In conclusion, the pathogenesis of melanoma is very complex because numerous genetic and epigenetic factors are implicated in its development and progression, but some of the showed mechanisms can be targets for new therapies.