a 61-year - old woman presented with a verrucoid pink - tan plaque on the right heel , measuring 3 cm in diameter , which was subjected to an excisional biopsy . there were no cutaneous lesions elsewhere , and the remaining physical examination also showed no abnormalities . histological analysis showed a well - demarcated , discrete area of hyperkeratosis and parakeratosis with epidermal acanthosis . the surface epithelium was permeated by an infiltrate of atypical mononuclear cells with pale eosinophilic cytoplasm , large nuclei , and prominent nucleoli . they were dispersed randomly throughout the epidermis , singly and in small nests , with the greatest density being in its basal aspect . the superficial corium contained similar cellular elements as well as a mixture of other inflammatory cells ( fig . 1 ) . immunostaining showed that the lesional cells were reactive for cd2 , cd3 , cd7 , cd43 , and cd45r0 . cd8 + lymphocytes were sparse , and cd7 labeling was less intense than that of the other lymphoid markers ( fig . there has been no recurrence of any cutaneous lesions 10 months after excision of the pedal tumor , and the patient is currently well . a 50-year - old man developed a 1-cm pearly white - tan lesion on the chest , which had evolved over approximately 3 years . in the previous 3 - 4 months , it had increased in size and began to burn and itch . histological examination of an excisional biopsy specimen showed epidermal acanthosis with marked exocytosis , creating a  sieve - like appearance . those elements manifested significant irregularities in the nuclear membranes , with nuclear hyperchromasia and pleomorphism , and the cytoplasm was amphophilic or vacuolated . immunohistochemical studies showed diffuse lesional reactivity for cd3 , but labeling for cd7 was significantly diminished . intraepidermal lymphoid cells were nearly all reactive for cd4 , with only scattered staining for cd8 ( fig . the patient is currently well , with no additional cutaneous lesions 16 months after the diagnosis . pr was first described by frederick woringer and pierre kolopp in 1939 , in strasbourg , france . the first documented case was that of a 13-year - old boy who had a lesion on his forearm that measured < 1 cm in diameter and had been present for 6 years ; it then enlarged quickly . original clinical diagnostic considerations included those of mf , melanocytic nevus , and paget 's disease ; an intraepidermal lymphoid infiltrate was observed microscopically . in 1973 , braun - falco and colleagues assigned the designation of  pagetoid reticulosis to this condition because of the intraepidermal pagetoid distribution of lymphoid cells , which were thought to possibly represent t cells . those authors believed that pr was a disease entity distinct from mf because of its localized nature and more marked lymphoid epidermotropism . revuz and colleagues later concluded that the woringer - kolopp disease and pr were one and the same condition . currently , it is still difficult to distinguish pr from other variants of mf by microscopy alone . indeed , the differential diagnosis of pr includes mf of the  palmaris et plantaris type . pr almost exclusively comprises dense intraepidermal lymphoid infiltrates with variable acanthosis ; few atypical cells are seen in the dermis , but the corium commonly contains mature lymphocytes and histiocytes . immunologically , the lesional cells in pr are typically cd4 + t cells , although examples with cd8 + and cd4-/cd8- phenotypes have also been described . the cellular proliferation rate , as measured immunohistologically with the ki-67/mib1 antibody , is usually > 30% , and cd30 reactivity may be present as well . in comparison , classical mf typically manifests both epidermal and dermal components ; the latter comprise a polymorphous cell population consisting of neoplastic and mature lymphocytes , histiocytes , plasma cells , and eosinophils . clinically , typical mf lesions are most often thin plaques on the distal extremities and trunk . immunologically , the tumor cells are cd4 + with a low proliferation index ( < 10% ) , and they are usually cd30- . despite those differences , the world health organization has recently classified pr as a unilesional variant of mf . however , it seems that this is not always the case . in a study by haghighi et al . , some patients with pr had clinically progressive lesions that required aggressive therapy . another publication suggested that it was sometimes difficult to distinguish pr from mf of the  palmaris et plantaris type , and that the latter cases could require active treatment . it is important to include other aggressive t - cell lymphomas in the differential diagnosis of pr . for example , in one reported case , a patient with high - grade peripheral t - cell lymphoma was erroneously categorized initially as pr . another similar example was that of adult t - cell lymphoma / leukemia that was first thought to represent pr ; it likewise pursued an aggressive clinical course . immunohistochemical analysis of the lesions and thorough clinical correlation are necessary to avoid such problems . recent investigations of t - cell receptor gene rearrangements in pr have shown that either tcr or tcr may be aberrant . recently documented cases of pr   have included patients of all ages , including children . localized perioral lesions have also been reported   as well as a generalized form of the disorder known as ketron - goodman disease . on dermoscopy , pr has been said to show features that are similar to those of bowen 's disease . several treatments have been employed in pr cases , such as topical steroids , topical nitrogen mustard , light therapy , interferon alpha-2b , localized   and modulated   radiation therapy , imiquimod , alitretinoin , and fractional laser - assisted photodynamic therapy . in the reported experience of lee et al . their features and a review of the literature support the conclusion that pr is a unilesional variant of mf with distinctive clinicopathologic features . the approval of the authors ' institutional review board was obtained for this study as well as the patients ' consent .
pagetoid reticulosis is a rare variant of mycosis fungoides that presents with a large , usually single , erythematous , slowly growing scaly plaque containing an intraepidermal proliferation of neoplastic t lymphocytes . 
 histopathologically , this disease has distinctive attributes . in this report , 
 we present two cases of pagetoid reticulosis , compare its microscopic features to those of  classical mycosis fungoides , and provide a brief review of the pertinent literature .