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pemphigus vegetans is a rare variant of pemphigus vulgaris which commonly involves the flexures and oral mucosa .
pemphigus vegetans is a rare form of pemphigus vulgaris comprising only 1 - 2% cases .
pemphigus vegetans is an autoimmune disease characterized by flaccid bullae or pustules that erode to form hypertrophic plaques involving predominantly skin flexures and mucous membranes .
the cutaneous lesions in the hallopeau type begin as pustules and heal as vegetating plaques whereas those in neumann type , with a worse prognosis , are characterized by vegetation developing during the course of pemphigus vulgaris .
we herein report an unusual presentation of localized pemphigus vegetans without mucosal lesions which initially involved only the left breast , and subsequently involved the left groin during follow - up .
a 62-year - old healthy woman presented to our dermatology out - patient department with single painful red colored elevated lesion covered with pustules on the left breast for 6 months .
there was no history of fever , any drug intake , eye or mucosal complaints , no past or family history of similar illness , no history of any topical application . on examination , a single well - defined polycyclic erythematous plaque of size 6  7 cm with pustules concentrated mainly at the periphery of the plaque was present on left breast .
koh mount for fungus was negative , but based on clinical appearance probable diagnosis of tinea corporis was kept , and she was started on oral fluconazole 150 mg once a week and terbinafine cream local application twice daily for 2 weeks . on subsequent follow - up after 2 weeks , there was no improvement , but the lesion in the left breast had progressed and involved the entire left breast to form a single well - defined moist , verrucous vegetating plaque of size 810 cm with multiple pustules , yellow to brown colored crusts at places , and some raw oozy areas . plaque was surrounded by a broad rim of erythema [ figure 1a ] .
she also developed similar verrucous lesion in the left groin on subsequent 2 weeks follow - up [ figure 2a ] .
nikolsky 's sign was negative and tzanck smear showed eosonophils , but no acantholytic cells .
gram stain for bacteria showed only mixed inflammatory infiltrate with eosinophil predominance and acid fast bacteria staining was negative .
routine laboratory studies including complete blood count , c reactive protein , erythrocyte sedimentation rate , liver and renal function tests , and chest x - ray were all within normal limits .
biopsy specimens were obtained from the right breast with the differential diagnosis of pemphigus vegetans , pyoderma gangrenosum .
well - defined moist , vegetative plaque studded with multiple pustules healed hyperpigmented plaque moist , verrucous plaque of groin patient was started on oral prednisolone 40 mg once daily with which she showed dramatic response within a week .
histopathological examination [ figures 3a  c ] showed suprabasal cleft with acantholytic cells , numerous eosinophils , intraepidermal eosinophilic abscesses , and dense inflammatory infiltrate in the dermis . as the biopsy was taken from an early pustule , that might be an explanation for the absence of hyperkeratosis and papillomatosis in the present case .
direct immunofluorescence ( dif ) revealed intercellular immunoglobulin g ( igg ) deposits in the epidermis [ figure 4 ] .
suprabasal cleft with acantholytic cells and intraepidermal eosinophilic abscess suprabasal cleft with acantholysis increased number of eosinophils dif shows intercellular immunoglobulin g ( igg ) deposits in the epidermis in a fish - net pattern
the histopathology in pemphigus vegetans exhibits epidermal hyperplasia , papillomatosis , and intraepidermal eosinophilic abscesses as the lesions age .
histopathology of pemphigus vegetans seem to differ from pemphigus vulgaris by an eosinophilic response , formation of eosinophilic microabscesses and extent of vesiculation . the immunofluoresence findings in pemphigus vegetans are indistinguishable from those of pemhigus vulgaris .
patient in discussion posed diagnostic challenge as she had limited cutaneous involvement , no mucosal involvement , and atypical site of presentation .
we kept the possibility of pemphigus vegetans , hallopeau type on the basis of intertriginous involvement , pustular and vegetative lesions supported , by histopathological examination with predominant eosinophilic infiltrate .
all the above findings were confirmed by direct immunofluoresence showing immunoglobulin g ( igg ) deposits in a fish - net pattern .
various conditions that have to be kept in the differential diagnosis include the vegetating lesions of other bullous autoimmune skin diseases , such as bullous pemphigoid or immunoglobulin a ( iga ) pemphigus , the chronic inflammatory plaques of hailey - hailey disease , and especially vegetating pyoderma .
both diseases show similar clinical and histopathological findings , but in pyostomatitis vegetans the immunofluorescence findings are characteristically negative .
although the lesions in pemphigus vegetans can occur at any site , solitary lesion involving unusual sites like scalp , soles and at skin graft recipient site have rarely been described in literature .
very rarely solitary vegetating plaque mimicking pemphigus vegetans could be the cutaneous presentation for paraneoplastic pemphigus , in that situation associated malignancy , severe mucosal involvement , and other criterion will be helpful in reaching the final diagnosis . till date , to the best of our knowledge , primary involvement of the breast without mucosal involvement has not been reported .
after detailed and exhaustive work , she was being diagnosed as a case of pemphigus vegetans .
she was administered oral steroid , which was tapered slowly over a period of 4 weeks .
she showed excellent response ; complete healing of plaques with hyperpigmentation occurred over a period of 2 weeks . till date , even after 6 months of stopping steroid she had not shown any symptom or sign of relapse .
to emphasize pemphigus vegetans , although a variant of pemphigus vulgaris , can present at atypical site or show limited involvement without involving mucosa giving a diagnostic challenge .
so , in routine dermatological practice resistant pustular plaque not responding to antifungal or antibacterial treatment , pemphigus vegetans can be kept as a good differential . in our case , the lesions were localized in the left breast and groin , without mucosal involvement .
pemphigus vegetans is a rare variant of pemphigus vulgaris . 
 a 62-year - old woman presented with erythematous moist vegetative plaque on the left breast and left groin . 
 there was no mucosal involvement . 
 histopathological and direct immunofluorescence findings were suggestive of pemphigus vegetans . 
 she showed excellent response to oral steroids . 
 literature is scarcely available on the limited involvement with pemphigus vegetans without mucosal involvement .