A 42－year－old woman presented with a postauricular nodule, which was diagnosed as malignant melanoma using lymph node biopsy. She had several brown spots and papules on her head and neck. Papules on the parietal region of the head were diagnosed as pigmented nevi after histopathological examination. Positron emission tomography－computed tomography revealed cervical lymph node metastases ; however, no other distant lesions were found. She underwent cervical lymph node dissection and was subsequently treated with nivolumab for melanoma with unknown primary origin (MUP). However, multiple distant metastases occurred, with a marked increase in her serum lactate dehydrogenase levels. She died 85 days after the operation. Because MUP progressed rapidly, a detailed histopathological re－examination of the specimen was performed and revealed the lesion in the head to be the primary lesion. The rate of BRAF gene mutation is generally high in superficial spreading melanoma ; therefore, treatment with BRAF and MEK inhibitors could be effective. However, high melanin content in the tumor hinders the analysis of BRAF gene mutation.[Skin Cancer (Japan) 2020 ; 35 : 35－40]

An 86－year－old male, approximately 3.5 years after resection of a dermatofibrosarcoma protuberans on his head, presented with an ulcerated reddish tumor on the operated wound. Computed tomography showed bone destruction due to tumor invasion, and magnetic resonance imaging confirmed brain metastases. Skin biopsy revealed a dense proliferation of atypical spindle－shaped cells in the dermis and subcutis. The tumor cells were found to be CD34 negative, and the Ki－67 labeling index was 30%. COL1A1－PDGFB fusion transcripts were detected in the biopsy specimen ; hence, the patient was diagnosed with the recurrence of a fibrosarcomatous variant of dermatofibrosarcoma protuberans. He was administered imatinib mesylate and was treated with gamma knife radiosurgery for the brain metastases and radiotherapy for the recurrent lesions.[Skin Cancer (Japan) 2020 ; 35 : 41－46]

A 51－year－old woman presented with a prolonged history of a subcutaneous nodule on the right eyelid for 20 years. The nodule underwent a rapid increase in size over 4 months before presentation, making it difficult for her to open the right eyelid. Histopathological examination revealed nests and cords of small tumor cells extending into the entire dermis and deeper into the subcutaneous tissue. It was diagnosed as syringomatoid carcinoma. and surgical excision was performed with a safety margin of 10 mm. We resected the subcutaneous tissue on the cranial bone, a part of the temporal muscle and full thickness of the eyelid. The defect was reconstructed with mucosal transplantation, median forehead flap, and cheek flap. The patient is currently doing well with no evidence of recurrence or metastasis 2 years after surgery. Although there have been very few reports of dysfunction caused by syringomatoid carcinoma, this tumor can occur on the eyelids and may cause functional impairment as in this case. [Skin Cancer (Japan) 2019 ; 35 : 47－51]

A 70－year－old man presented with a 4－year history of erosion on the right dorsum of his foot, where he got a burn, for which he underwent conservative treatment at the age of 17 years. Squamous cell carcinomas (SCCs) developed twice on the burn scar when he was 51 and 66 years old, and both were surgically removed. One month after the operation for the second SCC, a keratotic nodule developed on the right inner ankle, which was also part of the burn scar. We surgically resected the tumor and diagnosed it pathologically as malignant melanoma in situ. Approximately 2 years later, an ulcer developed on his right inner ankle. The tumor was resected and diagnosed as malignant melanoma. As multiple different skin cancers may develop on burn scars over time, careful and long－term follow－up is essential for early diagnosis and treatment.[Skin Cancer (Japan) 2020 ; 35 : 52－57]

A 77－year－old woman presented to us with a 13 cm skin tumor on the left cheek with trismus. She had first noticed symptoms in the buccal mucosa of the cheek one month prior to the emergence of the rapidly growing tumor. The histopathological diagnosis of the tumor was squamous cell carcinoma. Clinical imaging revealed tumoral invasion to the circumjacent muscle tissue and bilateral cervical lymph node swelling with no distant metastasis. She received cetuximab combined with radiation therapy, followed by oral tegafur, gimeracil and oteracil. Her oral function improved with tumor regression and closure of the oral cutaneous fistula. She achieved complete clinical remission and has been disease－free for 4 years and a month.[Skin Cancer (Japan) 2020 ; 35 : 58－64]

A 9－year－old boy had a 10×7－mm² dark－brownish nodule on his right lower leg. The result of a partial biopsy performed at another hospital revealed the presence of a Spitz nevus. After the biopsy, the nodule extended by 4 mm in half a year ; thereafter, he was referred to our hospital. We performed a complete resection with a 5－mm margin. In our hospital, the first pathological diagnosis was malignant melanoma. Thereafter, we consulted dermatopathologists, and the nodule was finally diagnosed as an atypical Spitz tumor. The result of a sentinel lymph node biopsy was negative. No evidence of recurrence or metastasis was detected within 33 months postoperatively. The diagnosis of an atypical Spitz tumor requires immunohistochemistry and molecular studies as well as the evaluation of histological features. The identification methods for an atypical Spitz tumor, including sentinel lymph node biopsy, are challenging and controversial.[Skin Cancer (Japan) 2020 ; 35 : 65－70]

A 74－year－old man presented with an enlarging erythema on the right scrotum for 4 years. Based on histopathological findings, we diagnosed the patient with extramammary Paget’s disease (EMPD). After 4.5 years, right inguinal lymphadenopathy was detected, and lymphadenectomy was performed. In addition, radiotherapy was performed in the right external iliac and common iliac regions. After 8.5 years, lymphadenopathy was observed at the left clavicle, posterior diaphragmatic leg, and abdominal aorta, and one month later, the patient developed muscle weakness and numbness. For suspected brain metastasis of EMPD, we resected the region and provided postoperative irradiation. Nevertheless, the number of brain metastases increased, and the patient received additional whole－brain irradiation.

There have been a few reports of EMPD brain metastases. Particularly, this case is considered to be rare since metastases did not occur in other major organs.[Skin Cancer (Japan) 2020 ; 35 : 71－75]