Journal of Cutaneous Pathology最新文献

Crystal-storing histiocytosis (CSH) is a rare condition in which crystals accumulate in the cytoplasm of histiocytes and is usually associated with a lymphoplasmacytic neoplasm. Cutaneous CSH is extraordinarily rare and limited to case reports in the literature. We report two cases of this disease with cutaneous involvement. Case 1 was a 65-year-old male with a 4-month history of a pruritic eruption that started as a solitary pink to skin-colored indurated plaque on the anterior neck before progressing to involve the whole neck, chest wall, and face. Case 2 was a 54-year-old woman with a history of unspecified “lymphoma” who presented with a soft nodule on the forearm. Biopsies from both cases had similar findings and showed a proliferation of epithelioid cells with pink cytoplasm and intracellular crystalline structures infiltrating the dermis and subcutaneous fat. In the first case, the cells were positive for CD43, CD45, CD68, and IgG kappa, and in the second case, the crystals were positive for IgG lambda. Based on these findings, the patients were diagnosed with cutaneous CSH. We highlight this rare diagnosis and the importance of investigating an underlying lymphoplasmacytic neoplasm.

Necrotizing infundibular crystalline folliculitis (NICF) is a rare type of necrotizing folliculitis. The disease typically manifests as folliculocentric papules arising in a seborrheic distribution. Only 23 cases exist in the literature. Most reported cases have arisen spontaneously, but a small number of drug-induced cases in the setting of epidermal-derived growth factor, vascular endothelial-derived growth factor, or PD-1 inhibitor therapy have been reported. Colonization by bacteria and/or yeast occurs frequently. The etiology remains unknown, but some suggest a complex interplay with an aberrant microbiome, sebaceous gland dysfunction, and perturbed EGFR signaling in follicular infundibula. Histopathologic findings include rupture of follicular epithelium, neutrophilic inflammation, and nodular cup-shaped crystal deposits. We present a case of spontaneous, recurrent NICF in an inverse pattern in the inguinal region.

This report describes the clinical, onychoscopic, nail clipping, and histopathologic features of a malignant onychopapilloma. A 71-year-old male presented to our outpatient clinic for a stable, asymptomatic lesion on his left middle finger that had been present for 2 years. Prior nail clipping histopathology showed nail plate thinning with subungual abnormal onychocytes. Clinical examination revealed a 2-mm-wide streak of longitudinal xanthonychia extending to the proximal nail fold, with distal hyperkeratosis and onycholysis. Onychoscopy showed irregular longitudinal nail plate ridging with scattered punctate hemorrhagic foci. An excisional nail unit biopsy demonstrated cellular atypia of the nail bed epithelium, matrix metaplasia, longitudinal abnormal onychocytes, increased Ki-67 staining, and negative HPV immunoperoxidase staining, confirming the diagnosis of malignant onychopapilloma.

The Covid pandemic necessitated changes in traditional mentorship and educational roles. We offer our experience in structuring a virtual dermatopathology mentorship in the midst of the pandemic. Virtual mentorships have many benefits including ease of access, lack of geographic restrictions, and financial savings, though there still remains an important and irreplaceable role for in-person relationships.

Dermatofibrosarcoma protuberans (DFSP) is a cutaneous sarcoma with a high propensity for local invasion and recurrence. Although it is a rare event, the occurrence of multiple tumors in a single patient raises a diagnostic dilemma, as metastatic disease should be differentiated from multiple primary malignant events. In more than 90% of DFSP, a pathogenic t(17;22) translocation leads to the expression of COL1A1::PDGFB fusion transcripts. Karyotype analysis, fluorescence in situ hybridization, and RT-PCR can be useful ancillary studies in detecting this characteristic rearrangement, and sequencing of the fusion transcript can be used to support a clonal origin in metastatic and multifocal disease. However, previous reports have demonstrated variable sensitivity of these assays, in part due to the high sequence variability of the COL1A1::PDGFB fusion. Here, we report a patient who developed two distinct DFSP tumors over the course of 7 years. Chromosomal microarray analysis identified distinctive genomic alterations in the two tumors, supporting the occurrence of multiple primary malignant events.

We described an unusual combination of fibroblastic connective nevus (FCTN) already present at birth with underlying vascular anomalies. Overall, the lesion appeared as a large purplish-brown mass in the groin region up to the third of the right thigh, with partial spontaneous regression during the first three months of life. The FCTN observed exhibited several unusual characteristics: it was congenital, large in size, and located in the lower limbs. Finally, it represented the first case described in which an FCTN arose in association with vascular anomalies.