Involvement of the genus Corynebacterium in the pathogenesis of pigmented intratarsal keratinous cyst.

Intratarsal keratinous cyst (IKC) is a benign cystic lesion of the eyelid that retains keratin flakes. IKCs are usually yellow to white cystic lesions but rarely become brown or gray-blue, making clinical diagnosis difficult. The mechanisms by which dark brown pigments are generated in pigmented IKC are unclear. The authors report a case of pigmented IKC that had melanin pigments within the lining of the cyst wall and within the cyst. Focal infiltrates of lymphocytes were observed in the dermis, particularly beneath the cyst wall in areas with more melanocytes and intense melanin deposition. These pigmented parts faced bacterial colonies inside the cyst, which were identified to be Corynebacterium species in a bacterial flora analysis. The pathogenesis of pigmented IKC in relation to inflammation and bacterial flora is discussed.

Significance of IL36RN mutation analyses in the management of impetigo herpetiformis: A case report and review of published cases.

Impetigo herpetiformis (IH) is a rare variant of generalized pustular psoriasis (GPP), which develops during pregnancy. GPP is associated with mutations of IL36RN, but it is still unclear whether the same is true of IH. A 20-year-old Japanese woman developed erythema and pustules on her trunk during the 27th week of her first pregnancy. Within 1 month, the skin lesions spread over her whole body, accompanied by fever. Skin biopsy revealed Kogoj's spongiform pustules in the epidermis and she was diagnosed with IH. Systemic administration of prednisolone failed to resolve the skin eruption, but it was partially improved by the addition of cyclosporin. The patient gave birth to a healthy female infant. After delivery, her erythema relapsed and the effect of granulocyte and monocyte adsorption apheresis was limited. Thus, secukinumab was administrated, and since then, she has maintained complete remission. Mutation analysis revealed a homozygous c.28C>T (p.Arg10X) mutation in IL36RN. Twelve cases of IH, including that presented here, have been reported together with the results of IL36RN genetic analyses, and 10 of the 12 cases occurred in East Asia (Japan and China) despite the fact that IL36RN mutations in GPP have been reported worldwide. Among 10 IH patients of East Asian descent, seven had IL36RN mutations, all of which were founder mutations causing GPP in East Asia: c.28C>T (p.Arg10X) or c.115+6T>C (p.Arg10ArgfsX1). Thus, East Asian founder mutations may play an important role in the pathogenesis of IH. IH patients with IL36RN mutations have a tendency to require biologics to resolve postpartum flare-ups or sustained psoriatic skin lesions. Because IL36RN mutation status may help predict postpartum flare-ups in IH patients, mutation analysis should be considered to enable preparation for biologic therapy of intractable flare-ups.

Benign neonatal hemangiomatosis with early regression of skin lesions: A case report and review of the published work.

A 2-day-old Japanese male infant was referred to our outpatient clinic for multiple cutaneous hemangiomas present since birth. Physical examination revealed 14 small, well-circumscribed red papules, scattered over the head, face, dorsum of the right hand, trunk, lower extremities, buttocks and penis. Ultrasound examination revealed no evidence of visceral involvement. Histological examination of a cutaneous lesion was consistent with infantile hemangioma, resulting in the final diagnosis of benign neonatal hemangiomatosis (BNH). The hemangiomas enlarged by 1 month of age and began to resolve at 2 months of age. Within the next month, the lesions had almost completely disappeared. BNH is a rare, non-heritable, self-limited, benign disease characterized by multiple cutaneous infantile hemangiomas and no or unremarkable visceral lesions. Generally, BNH lesions spontaneously regress within the first 1-2 years of life or within 4 months of onset. However, there have been no detailed reports about the time course of BNH. To our knowledge, 31 cases of BNH without hepatic hemangiomas, excluding this case, have been reported so far. Twenty-one of these cases demonstrated spontaneous regression of the cutaneous hemangiomas without treatment. In all cases, the cutaneous hemangiomas were present at birth. The median age at the beginning of spontaneous regression was 6.0 months (range, 1-12) and the median age at complete or almost complete regression was 15 months (range, 3-28). Cutaneous hemangiomas in BNH without hepatic hemangiomas undergo spontaneous regression within the first year of life.

Subcutaneous dermoid cysts on the eyebrow and neck.

We report a case of dermoid cysts on the right lateral eyebrow and anterior neck. Multiple concurrent dermoid cysts, as in the present case, are very rare. The differential diagnosis of dermoid cyst includes epidermoid (epidermal inclusion) cyst, trichilemmal cyst, pilomatrixoma, lymphatic malformation, and lipoma. In particular, thyroglossal duct cyst and midline anterior neck inclusion cyst are part of the differential diagnosis when the lesion is in the anterior neck.

Primary Amelanotic Rhabdoid Melanoma: A Case Report with Review of the Literature.

Primary rhabdoid melanoma (PRM) is a rare variant of melanoma. Herein, we describe a case of primary amelanotic rhabdoid melanoma and review the clinicopathological features of previously reported cases of PRMs. A 63-year-old Japanese man presented with a nonpigmented red granular tumor without peripheral pigmented macules on the left heel measuring 21 × 18 mm in size. Light microscopic examination revealed a tumor mass composed entirely of polygonal neoplastic cells resembling pulmonary alveoli. Tumor cells were also discohesive with bizarre nuclei, prominent nucleoli and large hyaline cytoplasmic inclusions. No melanin pigment was present. Tumor cells were strongly and diffusely positive for S-100, MART-1, HMB-45 and vimentin, while negative for desmin, αSMA and synaptophysin. According to previous reviews, PRM tends to be amelanotic and nodular. S-100 protein and vimentin stained in all cases contrary to low stainability for HMB-45, which was, by contrast, positive in our case. Prognosis of PRM remains controversial due to the very rare occurrence of this tumor and the small number of confirmed cases that have been reported. Recognition of this rare entity is important in clinical practice even for skillful dermatologists to avoid misdiagnosis with the other tumors and to determinate the subsequent treatment principles.

Blue Rubber Bleb Nevus Syndrome Showing Vascular Skin Lesions Predominantly on the Face.

An 81-year-old Japanese man presented with dark blue papules and nodules on his face. There were multiple soft papules and nodules, dark blue in color, compressive, and ranging in size from 2 to 10 mm. A few similar lesions were seen on the patient's right dorsal second toe and right buccal mucosa. There were no skin lesions on his trunk and upper limbs. The patient's past history did not include gastrointestinal bleeding or anemia. Histopathological examination showed dilated vascular spaces lined by the normal epithelium extending beneath the dermis and into the subcutaneous fat. Endoscopy of the gastrointestinal tract to check for colon involvement was not performed. X-ray images of the limbs revealed no abnormalities in the bones or joints. Laboratory investigations did not show anemia. Although we failed to confirm a diagnosis by endoscopy, the skin lesions, histopathological findings, lack of abnormal X-ray findings, and the presence of oral lesions as a part of gastrointestinal tract guided the diagnosis of blue rubber bleb nevus syndrome (BRBNS). Skin lesions of BRBNS occur predominantly on the trunk and upper limbs. However, the present case showed multiple skin lesions predominantly on the face. Therefore, it is important for clinicians to know about a possible atypical distribution of skin lesions in BRBNS.