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Background: Atrophic variant of dermatofibrosarcoma protuberans (DFSP) is a distinct form of DFSP., Case Presentation: Here, we report the case of a 19-year-old woman with a small congenital atrophic plaque on the right precordium. The lesion remained atrophic for more than 10 years. Several years earlier, a portion of the plaque became tuberous and enlarged. Physical examination revealed a 25 × 30 mm erythematous atrophic plaque surrounded by three hard, smooth, and orange-colored nodules of varying sizes on the right precordium, along with visible subcutaneous adipose tissue and cutaneous veins. Biopsy of the nodule and atrophic plaque revealed dense proliferation of spindle-shaped tumor cells from the dermis to the subcutaneous adipose tissue, and positive immunostaining for CD34 and vimentin in addition to negative staining for factor XIIIa and α-smooth muscle actin. Reverse transcription polymerase chain reaction (RT-PCR) of the tumor tissue revealed the presence of a COL1A1-PDGFB fusion gene. Thus, congenital atrophic dermatofibrosarcoma protuberans was diagnosed. No metastasis to the lungs or regional lymph nodes was found on magnetic resonance imaging. Wide local excision and split-thickness skin grafting was performed and neither recurrence nor metastasis has been observed for 5 years and 8 months since the surgery., Conclusion: This case indicates that a congenital atrophic lesion could represent a quiescent phase of DFSP. Awareness of this rare condition can aid with early diagnosis and thereby improve the prognosis of DFSP.

Dermatofibrosarcoma protuberans (DFSP) is an uncommon, slow growing, sarcoma of dermal and subcutaneous tissue with an infiltrative growth pattern. Although DFSP has a high rate of local recurrence, it rarely metastasizes. DFSP is characterized by a chromosomal translocation involving the collagen type I a 1 (COL1A1) gene on chromosome 17 and the platelet-derived growth factor B-chain (PDGFB) gene on chromosome 22. Various exons of the COL1A1 gene have been reported to be involved in the fusion with exon 2 of the PDGFB gene. In this study, we examined the COL1A1-PDGFB fusion transcripts using frozen specimens from three patients with DFSP. The molecular biology study with reverse transcriptase polymerase chain reaction (RT- PCR) and sequencing showed that the ends of exons 25, 31, and 45 in the COL1A1 gene were fused with PDGFB. The exon 2 of the PDGFB gene fused with exon 31 of the COL1A1 gene was a novel fusion gene.

Melanoma and other benign or malignant pigmented skin tumors can significantly overlap in their clinical and dermoscopical presentations. Thus, pigmented skin lesions may be misdiagnosed in a large number of cases. An extensive review of the published work provides numerous examples of benign lesions mimicking melanoma. Although a number of melanocytic nevi may have been identified as melanomas, information about their clinical appearance is limited. In this report, we present the clinical appearances of two melanocytic nevi on the vulva and the upper extremity that were difficult to diagnose clinically. Detecting melanoma at an early stage is of the utmost importance. However, more attention should be given to the diagnostic accuracy of benign pigmented skin lesions, which otherwise may be diagnosed and treated as melanoma.

A 70-year-old Japanese man presented with a 5-year history of refractory indolent onycholysis of the little finger of the right hand. Roentgenograms did not show involvement of the bone. Histological examination revealed an epithelial tumor consisting of lobular masses varying in size. The tumor was composed of keratinocytes varying in atypicality and showed infiltrative growth into the dermis but not into the phalangeal bone. The tumor had cystic structures composed of eosinophilic amorphous keratin and a surrounding thin layer of keratinocytes. Characteristically, the epithelium in the center of the tumor abruptly changed into amorphous keratin without the formation of intervening keratohyaline granules. From these findings, the mass was diagnosed as onycholemmal carcinoma. Immunohistochemically, the tumor showed a keratin profile comparable to that of the nail bed epithelium and a smaller number of Ki-67-positive proliferating tumor cells compared with those of a previous case of onycholemmal carcinoma.

Intravascular lymphomatosis (IVL) is a rare type of lymphoma with a poor prognosis. Its distinctive clinical and histopathologic features are generated by the proliferation of neoplastic mononuclear cells within blood vessels. We describe a patient with IVL of the skin as a manifestation of a recurrent diffuse large B-cell lymphoma of ureteral origin. Lymphoma cells were located both within the vessels and the parenchyma in an early cutaneous lesion. After recurrence in the skin, lymphoma cells gradually located only in the vascular lumina. This transition suggests that cells localized within the vessels were selected as a consequence of chemotherapy. Immunohistochemical examination revealed that the expression of surface adhesion molecules of lymphoma cells did not significantly change. The results of polymerase chain reaction revealed that the ureteral and cutaneous tumors were identical in clonality. Our findings suggest that conventional diffuse large B-cell lymphoma can change into IVL.