The patient was an 83－year－old man with a huge multinodular mass in the right lower leg. Based on the pathological findings, we diagnosed squamous cell carcinoma. Positron emission tomography－computed tomography showed swelling with enhancement in the popliteal, inguinal, and pelvic lymph nodes on the affected side, with no findings in other lymph nodes or organs. We resected the tumor with a 2 cm horizontal margin on the periosteum and confirmed negative margins. Pathology showed numerous immunoglobulin (Ig)G4－positive plasma cells infiltrating the tumor stroma. The popliteal and inguinal lymph nodes were infiltrated by IgG4－positive plasma cells without metastases. The high serum IgG4 level of 250 mg/dL but the absence of multiorgan involvement prompted the thought that it was IgG4－positive reactive lymphadenopathy rather than IgG4－related disease. We discussed the involvement of IgG4－positive plasma cells in tumor stroma or reactive lymphadenopathy.[Skin Cancer (Japan) 2023 ; 38 : 1－6]

A 72－year－old male noticed a tumor on the left upper back approximately 7 months before his referral to our hospital, which grew rapidly. A 20 cm oval, elastic, and soft mass with moist and uneven surface and satellite lesions was observed during his visit to our hospital. Lymphadenopathy was observed in both axillae. The skin biopsy revealed trabecular proliferation of squamoid atypical keratinocytes. Computed tomography showed multiple lymphadenopathies in the mediastinum and multiple liver metastases. The day following his admission, disorientation and dysarthria were observed, and magnetic resonance imaging revealed multiple cerebral infarctions. He was diagnosed with Trousseau syndrome ; treatment with dalteparin sodium resulted in recovery without paralysis. The dorsal mass and swollen lymph nodes in both axillae were dissected as palliative care, followed by chemotherapy with carboplatin and epirubicin. After the first course of chemotherapy, he died of gastrointestinal bleeding. [Skin Cancer (Japan) 2023 ; 38 : 7－11]

The patient was an 87－year－old woman. She underwent electrocautery approximately 40 years ago for unexplained bleeding from her right middle finger. Thirty－eight years after, she noticed hornified skin on the tip of the same finger. It was resected and diagnosed as tubular adenoma. After a year, the mass enlarged, and magnetic resonance imaging revealed a lysis of her distal phalanx. Amputation of the distal phalanx was performed. Pathologically, the tumor had a nodular and glandular arrangement below hyperkeratosis. Immunohistopathologic examination showed that the tumor consisted of glandular epithelial cells whose lumina were positive for carcinoembryonic antigen and epithelial membrane antigen and myoepithelial cells, which were positive for p63, CK5/6, and S－100 proteins. It was diagnosed as digital papillary adenocarcinoma (DPA). DPA has a high local recurrence rate, and there are reports of death due to distant metastasis, but there is currently no effective treatment for metastasis.[Skin Cancer (Japan) 2023 ; 38 : 12－16]

Kesennuma is a city in Miyagi Prefecture, Japan. The city was affected by population decline between 1980 and 2021. The population of Kesennuma was under 60,000 as of June 1, 2022. A total of 28 patients (6 men and 22 women) were treated, and their records were reviewed in the Department of Dermatology at the Kesennuma City Hospital between 2017 and 2021. Stage 0 accounted for 50%, stage I for 14.3%, stage II for 21.4%, stage III for 14.3%, and stage IV for 0%. The statistical data of the Kesennuma City Hospital (a rural hospital) was different from that of the annual report of the nationwide survey of melanoma in Japan.[Skin Cancer (Japan) 2023 ; 38 : 17－21]

A 63－year－old man presented with a 7－month history of a nontender pigmented skin mass on his left forearm. The tumor appeared as an elevated red lesion with black patches and measured 25 × 20 mm in size. We performed surgical excision with a 2－mm margin. Histopathological examination revealed pilomatricoma, which recurred 1 year and 5 months after surgical resection. We subsequently performed surgical re－excision with a 1－mm margin. Histopathological evaluation confirmed diagnosis of malignant pilomatricoma. Wide resection was performed with a 20－mm margin, and the defect was reconstructed using a skin graft. No recurrence was detected during 3－year follow－up.[Skin Cancer (Japan) 2023 ; 38 : 22－28]

A 55－year－old man was suspected of having lung cancer with cutaneous metastasis based on abnormal shadows in the left pulmonary hilar region and subcutaneous nodules in the abdomen and forearm. Positron emission tomography－computed tomography showed involvement of the liver, bone, lymph nodes, and subcutaneous nodules. Based on the skin and transbronchial lung biopsy pathological findings, a diagnosis of multiple metastases of Merkel cell carcinoma with an unknown primary origin was made. All lesions disappeared after four doses of avelumab ; however, the patient developed grade 3 myasthenia gravis. Avelumab was discontinued, steroids were administered, and plasma exchange was performed, but the patient improved poorly, and the drug could not be re－administered. Four months after avelumab discontinuation, the tumor recurred and spread rapidly throughout the body. Chemotherapy was ineffective ; therefore, it was discontinued. Myasthenia gravis is an immune－related adverse event with high mortality rate. Its management is directly related to patient prognosis ; therefore, prompt and adequate therapeutic intervention on symptom onset is essential.[Skin Cancer (Japan) 2023 ; 38 : 29－36]