Shimshak, Serena J E

ABSTRACT We report a case of a 71‐year‐old female with acute myeloid leukemia (AML), treated with chemotherapy and hematopoietic stem cell transplant (HSCT), who developed a clonally related non‐Langerhans cell histiocytosis (NLCH). She presented with pink papules on the mid‐upper cutaneous lip and thighs 3 months following HSCT. Skin biopsies revealed a dermal proliferation of cells with eosinophilic cytoplasm. Immunohistochemistry (IHC) studies demonstrated positivity for CD68, CD163, BRAF, cyclin D1, and Factor XIIIa and negativity for CD1a, S100, MPO, and CD20. Next‐generation sequencing (NGS) with a comprehensive myeloid panel revealed corresponding pathogenic mutations to her AML, including BCOR Q176fs*40, IDH1 R132C, and TP53 Y163N, and an additional BRAF V600E mutation. Additional mutations in DNMT3A and KMT2A associated with her AML were not identified. These findings supported the diagnosis of NLCH sharing a clonal origin with the patient's AML. Work up demonstrated isolated cutaneous involvement without AML relapse; therefore, the skin lesions were treated with shave excision, topical tacrolimus 0.1% ointment, and topical clobetasol 0.05% cream without further systemic treatment. The acquired BRAF V600E mutation illustrates the potential for divergent myeloid differentiation and likely explains the emergence of a clonal NLCH after successful AML treatment. Genetic analysis in NLCH can establish clonality with associated hematologic malignancies, uncover actionable mutations, and guide treatment.

AbstractHistiocytoid Sweet syndrome (H‐SS) is a histopathological variant of Sweet syndrome (SS) defined by cutaneous infiltration of immature myeloid cells morphologically resembling histiocytes. The association of H‐SS with underlying malignancy, particularly myelodysplastic syndromes, is well‐established. Myelodysplasia cutis (MDS‐cutis) has been proposed to describe cases historically diagnosed as H‐SS but characterized by shared clonality of the myeloid infiltrate in skin and bone marrow. Therefore, identifying patients who might have MDS‐cutis is critical for the management of the associated hematologic malignancy. VEXAS syndrome, an adult‐onset autoinflammatory disease, should also be included in the histopathologic differential diagnosis of H‐SS, as it shares clinical and pathologic features with MDS‐cutis. Through the presentation of two cases, we aim to highlight the defining features and key clinical implications of MDS‐cutis and VEXAS syndrome.

AbstractAn 11‐year‐old female was referred from an outside institution after a diagnostic biopsy and subsequent excision of a progressively enlarging reddish‐brown nodule demonstrated features concerning for a balloon cell nevus with severe atypia versus a high‐grade melanocytoma. Upon review of the initial biopsy specimen and molecular data, we favored the diagnosis to be consistent with a high‐grade melanocytoma with balloon cell changes while considering the possibility of balloon cell melanoma due to concerning histopathologic and genetic abnormalities. In this case study, we discuss critical diagnostic considerations in this rare pediatric case and highlight important pathologic and clinical features of melanocytomas and balloon cell melanoma.

Abstract Background Immunosuppression following solid organ transplantation is a known risk factor for the development of posttransplant lymphoproliferative disorders (PTLD). Primary cutaneous T‐cell lymphoma (CTCL) occurring in the posttransplant setting is rare, which has made comprehensive understanding of this disease challenging. This study aims to further characterize the spectrum of clinicopathologic features of CTCL in solid organ transplant recipients (SOTR). Methods A retrospective chart review was performed for SOTR who were diagnosed with CTCL at a multi‐site academic medical center from January 1, 1998, to December 31, 2013. Eight patients fulfilled the inclusion criteria and were included in this study. Data collected included patient demographics, transplanted organ, the time between transplant and CTCL diagnosis, clinical presentation and rash morphology, a histological subtype of CTCL, immunosuppression regimens, and patient status. Twelve diagnostic skin biopsies for five patients were examined and reviewed by a board‐certified dermatopathologist. Results Six (75%) out of the eight patients were men, two (25%) were women, and the median age was 53 years. The median time from the date of transplant to the diagnosis of CTCL was 8.2 years. Transplanted organs included the liver (4), kidney (3), and heart (1). Clinical presentation varied from papulonodules, comedone‐like lesions, intense pruritis, and scaly erythematous eruptions. The most common histologic presentation was folliculotropic mycosis fungoides (FMF) (7/12). Epstein–Barr virus‐in situ hybridization (EBV‐ISH) was negative in all specimens. Conclusions We emphasize the rarity of CTCL among SOTR. Although rare in the general population, the FMF subtype appears to be disproportionately seen in SOTR compared with other CTCL.

This review article examines evidence supporting the use of oral therapies in treating idiopathic, actinic, and metabolically induced skin hyperpigmentation. A thorough review of the literature regarding oral treatments for hyperpigmentation was systematically conducted through PubMed. Keywords used in the primary search include “Hyperpigmentation,” “Melanosis” or “Melasma,” “Lightening,” “Oral,” and “Therapeutics.” The search was limited to the English language, and no timeframe restrictions were implemented. Numerous orally administered therapies have been proposed for the treatment of skin hyperpigmentation. There is an abundant body of literature demonstrating the efficacy of orally administered tranexamic acid, glutathione, isotretinoin, and proanthocyanidin. It is reasonable to expect that the most effective oral therapies will address known underlying causes of hyperpigmentation such as thyroid disease, diabetes, and hormonal imbalance. Improvement due to oral therapy of otherwise unresponsive skin hyperpigmentation or hyperpigmentation of unknown cause is less predictable. This review is limited by the strength of evidence contained within the available studies. Clinical studies investigating the treatments discussed within this article are limited in number, at times lack blinding in the study design, and are based on small sample sizes. Based on existing research, the most promising oral remedies for hyperpigmentation appear to be tranexamic acid, glutathione, isotretinoin, and proanthocyanidin. Additional studies to better establish safety and efficacy are necessary.