Profibrotic Subsets of SPP1+ Macrophages and POSTN+ Fibroblasts Contribute to Fibrotic Scarring in Acne Keloidalis.

Acne keloidalis is a primary scarring alopecia characterized by longstanding inflammation in the scalp causing keloid-like scar formation and hair loss. Histologically, acne keloidalis is characterized by mixed leukocytic infiltrates in the acute stage followed by a granulomatous reaction and extensive fibrosis in the later stages. To further explore its pathogenesis, bulk RNA sequencing, single-cell RNA sequencing, and spatial transcriptomics were applied to occipital scalp biopsy specimens of lesional and adjacent no-lesional skin in patients with clinically active disease. Unbiased clustering revealed 19 distinct cell populations, including 2 notable populations: POSTN+ fibroblasts with enriched extracellular matrix signatures and SPP1+ myeloid cells with an M2 macrophage phenotype. Cell communication analyses indicated that fibroblasts and myeloid cells communicated by SPP1 signaling networks in lesional skin. A reverse transcriptomics in silico approach identified corticosteroids as possessing the capability to reverse the gene expression signatures of SPP1+ myeloid cells and POSTN+ fibroblasts. Intralesional corticosteroid injection greatly reduced SPP1 and POSTN gene expression as well as acne keloidalis disease activity. Spatial transcriptomics and immunofluorescence staining verified microanatomic specificity of SPP1+ myeloid cells and POSTN+ fibroblasts with disease activity. In summary, the communication between POSTN+ fibroblasts and SPP1+ myeloid cells by SPP1 axis may contribute to the pathogenesis of acne keloidalis.

Successful erlotinib rechallenge in an EGFR-mutant metastatic non-small cell lung cancer patient with afatinib-induced drug rash with eosinophilia and systemic symptoms: A case report.

Tyrosine kinase inhibitors (TKIs) are the standard treatment for epidermal growth factor receptor (EGFR)-mutant advanced-stage non-small cell lung cancer (NSCLC). However, TKIs can cause some severe adverse events, which are more prevalent within first-generation EGFR-TKI use than with second-generation inhibitors. Herein, we report a case of a patient with advanced-stage EGFR-mutant NSCLC who developed drug reaction with eosinophilia and systemic symptoms (DRESS) after receiving treatment with afatinib. The patient was successfully rechallenged with erlotinib, without manifestations of skin rash in the following 6 months. Hence, erlotinib may be considered a potential substitute for other EGFR-TKIs following DRESS occurrence.

Successful treatment of giant Bowen's disease with photodynamic therapy and subsequent imiquimod in a case with chronic arsenic exposure.

Multiple large lesions of Bowen's disease (BD) often appear in patients who have been under chronic exposure to arsenic. The treatment of such lesions is very challenging. Photodynamic therapy (PDT) has been considered a first-line effective treatment for BD. However, lesions larger than 2 cm are less responsive to PDT. We reported two giant BD lesions (> 10 cm in diameter), that were on a chronic arsenicosis patient's back, to be successfully treated with PDT and subsequent imiquimod occlusion overnight twice a week on the week after PDT. No recurrence was noted during the 12-month follow-up.

"Spade sign" and inflammation/fibrosis limited to the upper and mid-dermis as the pathognomonic features of acne keloidalis.

Acne keloidalis (AK) is one of the primary cicatricial alopecias and predominantly affects men of African descent. Reports in Asians are scant. This study aimed to retrospectively review the clinical and histopathological features of AK patients in southern Taiwan and identify the pathognomonic features of AK. There were 15 patients with histopathologically confirmed AK in National Cheng Kung University Hospital between 1988 and 2018. The median onset age was 24 years (range, 14-71). The male : female ratio was 14:1. In the acute stage of AK, the lymphocytic and neutrophilic peri-infundibular inflammatory infiltrates with microabscess formation and edema corresponded to the clinical finding of isolated papules or pustules. Subsequently, the inflammatory infiltrates involved the mid-dermis and the isthmus of hair follicles. The "spade sign", a thin and dilated space resembling the shape of a balloon or spade symbol of playing cards at the level of lower isthmus, was identified in eight biopsies from five patients and may be a pathognomonic sign in the subacute stage of AK. At the chronic stage, the segments of hair shafts remained in the upper to mid-dermis and induced chronic inflammation and extensive fibrosis, resulting in the clinical keloid-like appearance. The restriction of inflammation and fibrosis in the upper to mid-dermis was another unique and pathognomonic feature of AK.