Development of Halo Nevi in a Lung Cancer Patient: A Novel Immune-Related Cutaneous Event from Atezolizumab.

Immunotherapy-induced vitiligo is an immune-related adverse event (irAE) observed in metastatic melanoma patients treated with immune checkpoint inhibitors that target the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death-1 (PD-1) pathways. To date, the development of leukoderma, poliosis, and halo nevi during immunotherapy has largely been reported in metastatic melanoma patients. We report a case of immunotherapy-induced leukoderma presenting as halo nevi in a patient with non-small cell lung cancer (NSCLC) treated with atezolizumab, a programmed cell death ligand (PD-L1) antibody. Immunotherapy-induced vitiligo in metastatic melanoma patients may be associated with improved survival, but it remains to be determined whether its occurrence in non-melanoma cancers has the same prognostic significance.

J Drugs Dermatol. 2017;16(10):1047-1049.

Acquired Epidermodysplasia Verruciformis and Its Relationship to Immunosuppressive Therapy: Report of a Case and Review of the Literature.

INTRODUCTION: Epidermodysplasia verruciformis (EV) is a rare inherited dermatosis characterized by increased susceptibility to human papilloma virus infection. Acquired EV occurs in patients with compromised cell-mediated immunity, such as patients with HIV and transplant recipients. Optimal management of acquired EV has not yet been established, as cases are rare and are due to a variety of underlying conditions. Additionally, no distinctions have been made between different immunosuppressive medications and their respective link to EV. METHODS AND RESULTS: We report a patient with systemic lupus erythematosus who developed EV while on azathioprine and prednisone. The patient's lesions resolved completely after she was switched from azathioprine to mycophenolate mofetil. Her lesions recurred when her immunosuppressive regimen was again changed from mycophenolate mofetil to methotrexate. A review of the literature revealed azathioprine to be related to other cases of acquired EV. DISCUSSION: This case indicates a possible link between specific immunosuppressive drugs and the development of EV, allowing for new EV treatment considerations. In this case and previous cases, azathioprine is indicated as being particularly linked with the development of EV, while mycophenolate mofetil may be an immunosuppressive option that is less likely to induce EV in patients predisposed to this condition. J Drugs Dermatol. 2017;16(7):701-704.

Detection of Rickettsia rickettsii, Rickettsia parkeri, and Rickettsia akari in skin biopsy specimens using a multiplex real-time polymerase chain reaction assay.

BACKGROUND: Rickettsia rickettsii, Rickettsia parkeri, and Rickettsia akari are the most common causes of spotted fever group rickettsioses indigenous to the United States. Infected patients characteristically present with a maculopapular rash, often accompanied by an inoculation eschar. Skin biopsy specimens are often obtained from these lesions for diagnostic evaluation. However, a species-specific diagnosis is achieved infrequently from pathologic specimens because immunohistochemical stains do not differentiate among the causative agents of spotted fever group rickettsiae, and existing polymerase chain reaction (PCR) assays generally target large gene segments that may be difficult or impossible to obtain from formalin-fixed tissues. METHODS: This work describes the development and evaluation of a multiplex real-time PCR assay for the detection of these 3 Rickettsia species from formalin-fixed, paraffin-embedded (FFPE) skin biopsy specimens. RESULTS: The multiplex PCR assay was specific at discriminating each species from FFPE controls of unrelated bacterial, viral, protozoan, and fungal pathogens that cause skin lesions, as well as other closely related spotted fever group Rickettsia species. CONCLUSIONS: This multiplex real-time PCR demonstrates greater sensitivity than nested PCR assays in FFPE tissues and provides an effective method to specifically identify cases of Rocky Mountain spotted fever, rickettsialpox, and R. parkeri rickettsiosis by using skin biopsy specimens.

Merkel cell carcinoma: review.

Merkel cell carcinoma (MCC) is synonymous with primary cutaneous neuroendocrine carcinoma. It tends to affects elderly whites, but there is also an increased incidence among immunosuppressed patients. The recent identification of a novel polyomavirus associated with the tumor has stimulated renewed interest in its pathogenesis. MCC tends to show classic histologic features of a neuroendocrine carcinoma and is often positive for CK20, but nonclassic cytologic findings and unusual immunophenotypes may be observed and can lead to a diagnostic confusion. MCC needs to be distinguished from other primary cutaneous tumors with a small cell appearance and metastatic tumors. Surgical excision is the treatment of choice, but radiation therapy has also found to be effective. Sentinel lymph node biopsy has become an integral part of the staging of patients with MCC.

Minimal metastatic disease in sentinel lymph nodes in breast carcinoma: some modest proposals to refine criteria for "isolated tumor cells".

Axillary lymph node status is one of the most important prognostic factors in breast carcinoma. The weight of cumulative evidence suggests that the development of the sentinel lymph node (SLN) biopsy procedure has not only allowed for accurate lymph node-staging but has also helped avoid the morbidity of a full axillary dissection in those patients who are unlikely to have metastatic tumor in that location. The detection of metastases in SLNs is facilitated by the, now relatively routine, enhanced histopathologic examination via step-sectioning and immunohistochemistry. In clinical terms, the finding of a metastatic deposit that measures between 0.2 and 2 mm, that is, "micrometastasis" in a SLN is largely noncontroversial; however, the presence of smaller metastatic foci detected either by routine hematoxylin and eosin stain or by cytokeratin immunostain [<0.2 mm, ie, so-called "isolated tumor cells (ITCs)"] has remained problematic since the advent of the SLN biopsy. In this communication, attention is drawn to the broad morphologic range of metastatic disease in SLN that may be placed in the category of so-called ITC. To facilitate the reproducible classification of the various strata of minimal metastasis in sentinel lymph nodes, we recommend the following: (1) the term "isolated tumor cell" (note singular form) be restricted to cases that show the presence of only a single tumor cell. (2) In situations where there are multiple isolated single cells and/or cell cluster(s) present and each cluster measures<0.2 mm, the term "submicroscopic metastasis" be adopted and an actual count of tumor cells present may be given. (3) Restrict the use of the term micrometastasis to cases wherein the largest metastatic focus is larger than 0.2 mm but smaller than 2.0 mm.