ABSTRACT
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.
ABSTRACT
Isotretinoin is a first-generation retinoid initially approved for the treatment of severe cases of acne vulgaris (nodulocystic acne). Because of its broad anti-inflammatory and immunomodulatory properties, it has been used beyond its initial approval in a myriad of other indications. Adverse effects of isotretinoin vary from xerosis to teratogenicity. Herein, we reviewed the literature, through date-unlimited PubMed search, from inception till December 2019, using the following search terms: "low-dose isotretinoin" and "dermatology," "isotretinoin and safety," "isotretinoin, off-label uses," "isotretinoin and male fertility," "isotretinoin, iPLEDGE system," aiming to deliver a therapeutic update relevant to clinical practice. All English-language articles were considered with no limitation based on the articles' type. Low-dose isotretinoin is not limited to old and novel dermatological conditions, but also showed promising results in the field of infertility and safety in the field of gastroenterology. We also highlight on the safety profile of the drug and experts' recommendations to enhance safety measures to decrease fetal risk while on isotretinoin.
