Background: Sarcoma may show similarities to malignant melanoma in terms of morphologic and immunohistochemical aspects, hence making it difficult to differentiate between these two neoplasms during the diagnostic process. This systematic review aims to summarize available evidence on cases of sarcoma that were initially diagnosed as melanoma. Methods: A comprehensive search was conducted including MEDLINE/Pubmed, EMBASE and SCOPUS through March 2023. We included case series and case reports of sarcoma patients that were initially diagnosed as malignant melanoma. PRISMA guidelines were followed. Results: Twenty-three case reports and four case series with a total of 34 patients were included. The clinical presentation was heterogeneous, and the most involved anatomical regions were lower limbs (24%), head/neck (24%) and upper limbs (21%). IHC positivity was reported for S100 (69%), HMB45 (63%), MelanA (31%) and MiTF (3%). The main reasons for second assessment were unusual presentation (48%) and uncertain diagnosis (28%). EWSR1 translocation was investigated in 17/34 patients (50%) and found positive in 16/17 (94%). The final diagnosis was clear cell sarcoma (50%) or other soft tissue sarcomas (50%). Conclusions: Melanoma and some histotypes of sarcoma share many similarities. In case of atypical lesions, a second diagnosis should be considered, and ESWR1 translocation should be investigated.

Word count: 1329Tables:NoneFigure: 3References: 9Conflicts of interest: NoneAcknowledgements: NoneAuthor Contributions: All authors contributed to designing and conducting the work, drafting, and revising the manuscript and approved the final version for submission.ABSTRACTBACKGROUND: We present a case of sirolimus-induced DRESS syndrome in a stem cell transplant patient. Sirolimus is an immunosuppressive drug that inhibits the mTOR pathway. It is commonly used in organ transplants to prevent rejection. While no sirolimus-induced DRESS cases have been reported, allergic reactions with everolimus, a similar drug, have been documented. DRESS syndrome is a severe drug reaction characterized by fever, rash, and organ involvement. Diagnosis is based on clinical findings and laboratory tests. Early recognition, discontinuation of the drug, and supportive care are crucial in managing DRESS syndrome, often involving systemic corticosteroids.CASE REPORT A 24-year-old man who had undergone haplo-TESE transplantation for acute lymphatic leukaemia presented with diffuse itchy eczematous lesions. Initially diagnosed as atopic dermatitis, he received topical steroid therapy and NB-UVB phototherapy, but his condition worsened. Two months later, he returned to the emergency department with eczematous patches, xerosis, fever, chills, and generalized edema. His medical history included relapses of leukaemia, acute cutaneous graft-versus-host disease (GVHD), and Evans syndrome. He had been on sirolimus immunosuppressive therapy before the onset of symptoms. A skin biopsy revealed spongiotic dermatitis with dermal eosinophils, suggestive of drug reaction or atopic reaction. Based on the severity of the symptoms and histological findings, the patient was diagnosed with sirolimus-induced DRESS syndrome. Sirolimus was discontinued, and oral steroid therapy was initiated, leading to significant improvement. At the one-month follow-up, the patient was symptom-free and had lost the gained weight.CONCLUSION Although no cases of sirolimus-induced DRESS syndrome have been reported, allergic reactions with eosinophilia induced by everolimus have been documented. And since sirolimus and everolimus, both mTOR inhibitors, share a common mechanism of action, therapeutic indications, pharmacokinetics, adverse effects and drug interactions, it cannot be ruled out that sirolimus may trigger DRESS syndrome in patients with risk factors. In our case, the

Impetigo herpetiformis (IH) is a rare variant of pustular psoriasis with typical onset during the third trimester of pregnancy; it is characterized by erythematous plaques lined with sterile pustules and sometimes there may be systemic involvement. On the other hand, eczema herpeticum (EH) is defined as a disseminated skin infection by herpes simplex virus type 1, which mainly affects patients characterized by an impaired integrity of the skin barrier, mostly atopic dermatitis. We report the case of a 30‐year‐old woman, primigravida at 28 + 3 weeks of gestation, who after asymptomatic severe acute respiratory syndrome coronavirus 2 infection for about 7 days presented to the emergency room with a burning and itching rash on the trunk and limbs. She reported a long‐standing history of atopic dermatitis and recurrent herpetic eruptions. The diagnosis of EH was made and systemic therapy was set with excellent results. A few days later, the patient developed a pustular rash in the areas previously affected by EH, with histologic features of IH. A relation between EH and IH is thus suggested.

Background: Sarcoma may show similarities to malignant melanoma in terms of morphologic and immunohistochemical aspects, making it difficult to differentiate between these two neoplasms during the diagnostic process. This systematic review aims to summarize available evidence on cases of sarcoma that were initially diagnosed as melanoma. Methods: A comprehensive search of the MEDLINE/Pubmed, EMBASE, and SCOPUS databases was conducted through March 2023. We included case series and case reports of sarcoma patients that were initially diagnosed as malignant melanoma. PRISMA guidelines were followed. Results: Twenty-three case reports and four case series with a total of 34 patients were included. The clinical presentation was heterogeneous, and the most involved anatomical regions were lower limbs (24%), head/neck (24%), and upper limbs (21%). IHC positivity was reported for S100 (69%), HMB45 (63%), MelanA (31%), and MiTF (3%). The main reasons for a second assessment were unusual presentation (48%) and uncertain diagnosis (28%). EWSR1 translocation was investigated in 17/34 patients (50%) and found to be positive in 16/17 (94%). The final diagnosis was clear cell sarcoma (50%) or other soft tissue sarcomas (50%). Conclusions: Melanoma and some histotypes of sarcoma share many similarities. In cases of atypical lesions, a second diagnosis should be considered, and ESWR1 translocation should be investigated.

Deep cutaneous mycoses are fungal infections that affect the skin and its deeper layers, leading to significant morbidity if not promptly diagnosed and treated. While dermatophytes, particularly Trichophyton rubrum and Trichophyton mentagrophytes, are the most common causative agents, other fungi such as Candida spp., Aspergillus spp., and Fusarium spp. can also cause these infections, especially in immunocompromised individuals. The clinical presentation varies depending on the depth and extent of the infection, ranging from superficial erythematous lesions to firm subcutaneous nodules, ulcers, abscesses, or sinus tracts. In advanced cases, deep cutaneous mycoses can lead to osteomyelitis and bone destruction. Mycetoma, a chronic infectious disease affecting the skin, subcutaneous tissues, and bones, is considered a deep skin mycosis. It is endemic in certain regions and can mimic other conditions such as cutaneous tuberculosis or cancerous lesions, making accurate diagnosis challenging. Diagnosis typically involves clinical presentation, radiological findings, and microbiological culture, with molecular methods aiding in culture-negative cases. Treatment is challenging and may involve surgical debridement, antifungal/antibiotic therapy, and sometimes amputation. Prevention strategies include improving hygiene, raising awareness, and early diagnosis. We present a case of an immunocompetent farmer with a wrist lesion initially suspected as cutaneous squamous cell carcinoma but histologically diagnosed as eumycetoma, emphasizing the importance of considering deep mycoses in high-risk individuals and highlighting the heterogeneous clinical presentation of these infections.