A Rare Coexistence: Cutaneous Lobular Carcinoma with Pyoderma Gangrenosum.

BACKGROUND Pyoderma gangrenosum (PG) is a neutrophilic inflammatory disease associated with inflammatory and autoimmune conditions and malignancies. Previously identified links between PG and cancer have included hematological malignancies, solid-organ tumors such as gastric adenocarcinoma, and breast cancer. While specific histologic subtypes of breast cancer such as ductal carcinoma have been associated with PG of the extremities, the literature is limited on the association between PG and cutaneous metastatic lobular carcinoma. CASE REPORT We describe the case of an 84-year-old woman with recurrent cutaneous metastatic lobular carcinoma of the left anterior chest with concurrent pyoderma gangrenosum on her bilateral lower extremities. The patient was initially diagnosed with lobular carcinoma of the breast and underwent a left breast mastectomy and was in remission. One year later, she developed 2 lower-extremity ulcerations, which at the time were attributed to an injury and underlying venous stasis. She was referred to a wound care clinic, where the lesions worsened with surgical debridement. Six years later, she presented to the dermatology clinic with a rash on her chest wall and worsening of the ulcerations on her ankles bilaterally. Biopsies revealed lobular carcinoma metastatic to the skin of her anterior chest wall and histopathology consistent with pyoderma gangrenosum on her ankles. CONCLUSIONS This case demonstrates a unique presentation of worsening pyoderma gangrenosum due to metastatic malignancy in conjunction with a cutaneous manifestation of lobular carcinoma.

Mendelian Randomization Studies in Atopic Dermatitis: A Systematic Review.

Prior studies have found associations between atopic dermatitis (AD) and comorbidities, including depression, obesity, asthma, and allergic rhinitis. Although observational studies often cannot establish robust causality between potential risk factors and AD, Mendelian randomization minimizes confounding when exploring causality by relying on random allelic assortment at birth. In this study, we systematically reviewed 30 Mendelian randomization studies in AD. Body mass index, gut microbial flora, the IL-18 signaling pathway, and gastroesophageal reflux disease were among the causal factors for AD, whereas AD was causal for several medical conditions, including heart failure, rheumatoid arthritis, and conjunctivitis. These insights may improve preventive counseling in AD.