A rapidly growing phase is usually followed by involution. KA occurs on sun-damaged skin. There are many listed causative associations, which include some therapeutic agents. Debate continues as to whether KA is a variant of squamous carcinoma (SCC) or a separate entity. Reporting of KA versus SCC is markedly inconsistent. Reasons for inconsistency include overlapping microscopic criteria, variants of KA with more aggressive features, and possibly medicolegal concerns. Genetic studies have shown some differences between the 2 entities. Activation of apoptotic pathways has been demonstrated in KA. Genetic studies have shown a possible role of human polyomavirus 6 in the pathogenesis of at least some KAs. Given that some cases of KA have components that behave as conventional SCCs, KA can be considered as a low-grade variant of SCC with some genetic differences.
  A definite diagnosis of infectious granulomatous dermatitis (IGD) is difficult for both practicing dermatologists and dermatopathologists due to overlapping clinical and histomorphological features. We aimed to explore the role of multiplex polymerase chain reaction (PCR) for identifying a definite etiological agent for diagnosis and appropriate treatment in IGD in formalin-fixed paraffin-embedded tissue.
 
  Sixty-two cases of IGD were included, excluding leprosy. The histochemical stains including Ziehl-Neelsen, periodic acid-Schiff, and Giemsa were performed in all cases. A multiplex PCR was designed for detection of tuberculosis (TB) (IS6110 and mpt64), fungal infections (ITS1, ITS2; ZM1, and ZM3), and leishmaniasis (kDNA). The results of histomorphology, histochemical stains, and multiplex PCR were compared.
 
  Among 62 cases, the sensitivity rate of PCR detection for organisms was 16.7%, 0%, 100%, 72%, 75%, and 66.7% in patients with TB, suggestive of TB, leishmaniasis, fungal infections, and granulomatowith a clinicopathological correlation. This will augment in appropriate treatment and will reduce empirical treatment and morbidity in such patients.
  This study aimed to identify the clinical and histopathological characteristics of secondary extramammary Paget disease (EMPD) with underlying anorectal adenocarcinoma so as to differentiate it from primary cutaneous EMPD. Seventeen and 8 cases of primary and secondary EMPD with anorectal adenocarcinoma, respectively, were retrieved from the pathology archive and the clinical and histopathological features reviewed. The tumor samples from 21 cases were totally resected specimens, whereas 3 and 1 of secondary and primary cases were punch biopsied, respectively. All 8 (100%) cases of secondary EMPD presented evenly distributed perianal lesions. By contrast, 4 of 17 (23.5%) primary EMPD cases had perianal skin lesions and displayed an uneven, asymmetrical distribution around the anus. Fibroepithelioma of Pinkus-like changes and subepidermal mucin deposits with no or few invasive tumor cells were observed in 6 (75%) and 3 (37.5%) of the 8 secondary EMPD cases, respectively, although 3 secondary case samples wercases of secondary EMPD presented evenly distributed perianal lesions. By contrast, 4 of 17 (23.5%) primary EMPD cases had perianal skin lesions and displayed an uneven, asymmetrical distribution around the anus. Fibroepithelioma of Pinkus-like changes and subepidermal mucin deposits with no or few invasive tumor cells were observed in 6 (75%) and 3 (37.5%) of the 8 secondary EMPD cases, respectively, although 3 secondary case samples were small biopsy specimens. Both the histopathological changes were not observed in any of the 17 primary EMPD cases. Evenly circumferential perianal distribution, fibroepithelioma of Pinkus-like changes, and subepidermal mucin deposits without invasive tumor cells were characteristic to cases of secondary EMPD with anorectal adenocarcinoma. These clinicopathological features could be used to differentiate between secondary and primary EMPD.
  Lichen planus (LP) is a mucocutaneous immune-mediated disease of unknown etiology. It is more prevalent in women and usually occurs between the third and sixth decades of life. Oral lesions may or may not be associated with skin and genital lesions. Although the role of genetic factors is still undetermined, reports of LP in more than one family member are not uncommon. However, the occurrence of LP in monozygotic twins is rare. We report a rare case of 42-year-old female monozygotic twins presenting oral LP. This report is even rarer because one of the patients had cutaneous lesions of an unusual variant of LP (LP pigmentosus) and the other had an uncommon association with lichen sclerosus. The etiology and pathogenesis of LP are still uncertain.  https://www.selleckchem.com/products/zasocitinib.html  However, despite being rare, its occurrence in family members and monozygotic twins suggests that genetic factors are involved in its development.
 Lichen planus (LP) is a mucocutaneous immune-mediated disease of unknown etiology. It is more prevalent in women and usually occurs between the third and sixth decades of life. Oral lesions may or may not be associated with skin and genital lesions. Although the role of genetic factors is still undetermined, reports of LP in more than one family member are not uncommon. However, the occurrence of LP in monozygotic twins is rare. We report a rare case of 42-year-old female monozygotic twins presenting oral LP. This report is even rarer because one of the patients had cutaneous lesions of an unusual variant of LP (LP pigmentosus) and the other had an uncommon association with lichen sclerosus. The etiology and pathogenesis of LP are still uncertain. However, despite being rare, its occurrence in family members and monozygotic twins suggests that genetic factors are involved in its development.
  Distinguishing hypertrophic lichen planus (HLP) and squamous cell carcinoma (SCC) can be diagnostically challenging because of overlapping clinical and histopathological features. This study characterizes histopathological features in HLP and SCC, assessing their utility in diagnosing atypical squamous proliferations. We compared 12 histopathological features of 15 HLP and 11 SCC biopsies from the lower extremities. We then reviewed 16 cases that were diagnosed as atypical squamous proliferations with differential diagnoses of HLP versus SCC. Clinical follow-up allowed for retrospective categorization of these difficult cases as HLP or SCC. HLP showed significant differences in hyperorthokeratosis (P = 0.04), wedge-shaped hypergranulosis (P = 0.0033), and irregular psoriasiform hyperplasia (P = 0.004), whereas parakeratosis (P = 0.001), solar elastosis (P = 0.001), deep extension (P = 0.02), and perforating elastic fibers (P = 0.0001) were significant for SCC. A scoring system based on these significant differences was devised to aid the classification of difficult cases.