because mf is the disease of old age , coincidence with pregnancy is rare and only few cases have been reported . until now there is controversy about the effect of pregnancy on progression of mf and some studies reported that pregnancy appeared to have no impact on the course of early mf , but according to our case report and some other reports , it seems that pregnancy may have some deleterious effect on the clinical course of mf . mycosis fungoides ( mf ) , a subgroup of non - hodgkin 's t - cell lymphoma , is the most common type of primary cutaneous t - cell lymphoma , characterized by skin infiltration and occasionally systemic involvement . in one retrograde study pregnancy appeared to have no impact on the course of early mf , and no adverse effect was noted on pregnancy . this case report is about the deleterious effect of pregnancy on progression of mf , and until now this is the first case report about transformation of mf to cd30 + large t - cell lymphoma during pregnancy . a 30 years old woman with history of scaling erythematous skin lesions since eight years ago was presented to mf clinic of alzahra hospital of isfahan university of medical sciences . lesions first has been appeared on the scalp then spreaded to whole body ( erythroderma ) . two years earlier skin biopsy has been done and histologic diagnosis of skin biopsy was dermatitis . physical examination findings were : erythroderma with severe scaling , palmoplantar keratoderma imitating acquired ichthyosis and bilateral ectropion [ figure 1 ] . two skin - biopsy was performed , the first specimen histologically was compatible with dermatitis , but the histologic evaluation of the second one confirmed the diagnosis of mf . the ihc staining revealed that the infiltrating cells were cd2 + , cd4 + , cd8- , cd45ro+ , cd7- , cd30- . exfoliative erythroderma with ectropion the criteria for diagnosis of mf was completed ( clinical criteria , ihc staining and tcr gene rearrangement analysis ) . cbc , esr , crp , ldh , blood biochemistry , liver function tests and peripheral blood smear were within normal limits . patient staged as stage iiia , at this stage our treatment plan was systemic puva therapy ( 3 session per week ) and interferon alfa 2b ( 3 million unit 3 session per weeks , sc ) two weeks later patient returned to our clinic and stated that she was pregnant . at this time our treatment plan changed to nb - uvb therapy , but she rejected this plan and interrupted treatment until delivery . ichthyosiform erythroderma with bilateral groin lymphadenopathy two weeks of antibiotic therapy was started but lymphadenopathy persisted . [ figures 3 and 4 ] ihc staining of specimens revealed that infiltrating cells had the following markers cd2 + , cd5 + , cd4 + , cd8- , cd45ro+ , cd7- , alk1(- ) , cd30 strongly positive , ki67 positive in more than 90% [ figures 5 - 7 ] skin biopsy , epidermotropism of lymphocytes . h and e , 100 the lymph node is almost completely effaced and replaced by large lymphocytes . h and e , 400 lymph node cd30 , 100 bone marrow biopsy was normal . previous skin specimens were re - evaluated and anaplastic large cell transformation of mf was confirmed . incidence of mf is 0.3 per 100,000 person per year and , it is twice more common in men than women . the mean age of diagnosis in western countries is approximately 60 - 80 years . in this region of the world ( iran , isfahan ) the median age of mf patients is 43.14 years and the male : female ratio is 3:4 ( in contrast to reports from other countries ) . these epidemiologic characteristics would partially explain the occasional coincidence of pregnancy and mf in our patients in isfahan iran . in 1981 , vonderheid , et al . reported a woman with a long - standing eczematous eruption that her skin lesions exacerbated during each of her three uncomplicated pregnancies . three years after her last pregnancy , the eruption was diagnosed as mf developing into the tumour stage . in 2001 castelo - branco , et al . described a women suffering from stage iv - b mf who became pregnant three years after the disease had been diagnosed . in spite of interruption of her therapy during pregnancy , the pregnancy had no adverse effect on the course of mf . in another case report in 2001 echols , et al . described a 26-year - old black woman diagnosed to be suffering from mf ( the stage was not noted ) 1 year before she became pregnant . at the beginning of her third trimester , she presented with an acute exacerbation of mf , so she was treated with puva and topical steroids , with complete remission . on the other hand , in the report of iris amitay , et al . , in a series of seven women with early - stage mf , there was no evidence indicating that pregnancy changed the course of the disease . in two mf patients that each undergone two pregnancies during the course of their disease , this finding was consistent and pregnancy appeared to have no impact on the course of early mf . of ten cases of mf during pregnancy described above , two showed progression during gestation , but none of them had large cell transformation . patients with plaque - type or erythrodermic mf may develop cutaneous tumors with large cell histology . the cells of this tumor are at least four times greater in size than a small lymphocyte . when over 25% of mf cells changes to large cell or when small nodules of these cells are identified on histology the transformation is diagnosed . incidence rates of transformation in patients with mf have ranged from approximately 10 to 25% ; with variation according to the stage of mf at presentation . in one study , the cumulative probability of transformation in stages ii - b and iv of disease was estimated to be about 33% . in this study elevation of serum beta-2 microglobulin and/or lactate dehydrogenase ( ldh ) , mentioned as predictive for transformation ( p = 0.009 ) . in another study of 419 patients with mf , 45 were found to have transformed at a median time after diagnosis of 6.5 years . our case staged as iii - a , with normal ldh at presentation which during pregnancy progressed to anaplastic large cell lymphoma . on the basis of reports mentioned above , it seems that this transformation was too rapid and it seems that pregnancy had a deleterious effect on the course of mf in this patient . this case report suggests a probable relation between cd30 + large cell transformation of mf and pregnancy . it is better to discuss about the probable risk of pregnancy in young women with mf who are planning for pregnancy . this is the first case report of cd30 positive large cell transformation of mf during pregnancy .