Abstract Cutaneous T cell lymphoma (CTCL) is an uncommon diverse group of lympho-proliferative disorders involving the skin. They vary considerably in clinical presentation, microscopic features and immunophenotyping. The diagnosis is challenging, zealous, and often not easy. CD30+ve anaplastic large cell lymphoma is extremely rare. Its clinical spectrum varies from a solitary unifocal skin lesion of excellent prognosis to a multi focal systemic disease having a poor out come. The diagnosis is quite cumbersome, and often difficult. The differential diagnosis include from benign skin lesions to secondary cutaneous involvement by lymphoma. A correct diagnosis is integral with a complete metastatic/staging work up to avoid over treatment. The treatment options depend on extent of disease involvement and include surgical excision, surveillance, local radiotherapy, and systemic chemotherapy. The prognosis is good with unifocal local disease. We present here a very rare case of CD30+ ALCL of scrotal skin, in a middle aged male patient. Keyword: Scrotal skin, CD30+ NHL, Unusual site NHL, Cutaneous T cell lymphoma, CD30+ ALCL, NHL, Anaplastic large cell lymphoma, Royal hospital Oman. Introduction Primary cutaneous CD30+ ALCL (Anaplastic Large cell Lymphoma) is a rare cutaneous T cell lymphoma (CTCL) of middle age; which includes multiple diverse subtypes depending on presentation, pathology and immunophenotype. 1 Up to 25% are reported to regress spontaneously. 1 This neoplasm can present as unifocal or multifocal (10-25%) nodules occasionally with ulceration, as an ulcer or tumour commonly on the trunk and extremities. 2 In 2003, first case was reported as an unusual primary cutaneous CD30+ LCL presenting initially as ulcerative papules on the hands followed by an ulcerating nodule on the scrotum. 1 There are cases reported of secondary scrotal skin involvement by lymphoma. 4,5 Isolated involvement of scrotal skin by CD30+ ALCL is extremely rare with only a few cases reported in literature. 4 The CD30+ LCL is also reported after burns, organ transplant, or in people on immunosuppressive therapy and can be associated with B symptoms. 2,4 Hodgkin's Lymphoma can also involve skin but very rarely. 1,2,5,6 CD30+ lympho-proliferative disorders include a wide spectrum of disease with lymphomatoid papulosis at the benign end of the spectrum and cutaneous CD30+ anaplastic large-cell lymphoma (ALCL) at the malignant end. 1 Many described borderline lesions are somewhere in between. Cutaneous CD30+ (Ki-1) ALCL is clinically and pathologically heterogeneous group of lympho-prolifertaive disorders, leading to some difficulty in its diagnosis and subsequent classification. Expression of CD30 (an activation marker for B or T cells) in more than 75% of neoplastic cells characterizes this group of lympho-proliferative disorders. Cutaneous CD30+ ALCL can be subdivided clinically into a primary cutaneous form without extra-cutaneous involvement, or a systemic form of disease with secondary skin involvement at initial presentation. 6 The primary cutaneous form generally has a better prognosis than the systemic form with secondary skin involvement. Spontaneous regression of the primary cutaneous form may occur despite high-grade anaplastic cytology of neoplastic lymphocytes, in upto 25% of cases. Cutaneous CD30+ ALCL can be further classified into different groups according to histological features and patterns (e.g., pleomorphic, immunoblastic, monomorphic, small-cell predominant, Hodgkin disease-related, and other uncommon variants); immunophenotype (e.g., T, null, B, rarely B and T); and other clinical features, such as ALCL arising in patients who are HIV positive and ALCL occurring after another lympho-proliferative process. 7 Multiple patterns of cutaneous CD30+ ALCL are recognized, and three are recognized by the World Health Organization (common, lymphohistiocytic, and small cell); however, several others have been described in the literature, for example, neutrophil rich, subcutaneous, and inflammatory. Case Report A 59 year Omani male presented with complaints of lower abdominal pain, intermittent haematuria and progressive ulceration of right scrotal skin of 3 months duration. There was no associated co-morbid disease. There was a past history of Right hip surgery about 15 years back due to trauma, with no further details available. On clinical examination he was well with performance status 1 WHO, and weight 65 kg. The general physical examination was 1140 J Pak Med Assoc Anaplastic Large Cell Lymphoma of Scrotal skin Itrat Mehdi, 1 Indira Praseeda, 2 Bassim Jaffer Al-Bahrani, 3 Namrata Satayapal, 4 Assam Abdel Monem, 5 Suad Al Kharusi 6 Department of Medical Oncology, 1,3,5,6 Department of Pathology, 2 Department of Radiation Oncology, 4 National Cancer Centre, Royal Hospital Muscat, Oman. Case Report