peri - anal abscesses tend to form a significant portion of presentations to surgical units for management . quite commonly these cases are initially managed on an acute basis .
an abscess cavity caused by a haematological malignancy can be drained , but this does not remove the cause of the abscess as there is residual disease .
this case documents a recurrent presentation of peri - anal abscess subsequent to a lymphoma .
a 63-year - old male was transferred from a regional hospital with a non - resolving peri - anal abscess .
he initially presented with a trans - sphincteric abscess which was drained in theatre multiple times with progressive sepsis and localised necrosis .
initial cultures and biopsies showed mixed enteric flora and granulation tissue with no evidence of malignancy .
the patient did not have a significant travel history , was not immune - compromised and denied any history of ano - receptive intercourse .
patient 's co - morbidities included poorly controlled diabetes mellitus ( whilst on insulin and oral hypoglycaemic agents ) , ischaemic heart disease with percutaneous coronary stent placement within last 2 years and a recent femoral endarterectomy and aorto femoral bypass .
given the high likelihood of significant vascular disease , a computed tomography ( ct ) angiogram was done ( fig .  1 ) .
bilateral internal iliac artery stenosis was noted with complete occlusion of the inferior mesenteric artery and right internal iliac artery . a positron emission tomography ( pet )
magnetic resonance imaging ( mri ) of his pelvis was significant for a large posterior abscess cavity with soft tissue at the margins with a cavity tracking superiorly along the posterior rectal plane ( fig . 
the internal sphincter was noted to be necrotic on the last examination ( fig . 
4 ) with a horseshoe cavity and a 10-cm tract running up the posterior aspect of the rectum .
multiple biopsies were taken from the anal margin , abscess cavity and peri - anal tissue , and the histology was consistent with diffuse large b - cell lymphoma .
6 ) and there was positive in situ hybridisation ( ish ) for epstein - barr virus ( ebv ) ( fig . 
fluorescence in situ hybridisation ( fish ) was performed using a myc dual colour break apart probe ( 8q24 ) , and no rearrangement of the myc gene region was detected .
the combined morphological and fish features were not considered to be those of burkitt lymphoma . 

figure  1:ct angiogram showing i m a and right internal iliac artery completely occluded . 

figure  3:magnetic resonance image ( mri ) scan showing a large posterior abscess cavity with a cavity tracking posterior to the rectum . 

figure  4:necrotic internal sphincter and abscess cavity at the posterior aspect of the rectum . 

figure  7:ebv ish was positive indicating the presence of ebv encoded rna in the tumour cells .
ct angiogram showing i m a and right internal iliac artery completely occluded . pet scan showing disease localized to the peri - anal region . magnetic resonance image ( mri )
scan showing a large posterior abscess cavity with a cavity tracking posterior to the rectum .
ebv ish was positive indicating the presence of ebv encoded rna in the tumour cells .
a defunctioning colostomy was performed and a chop - r regimen initiated as definitive therapy .
lymphomas are classified into hodgkin and non - hodgkin lymphoma based on the presence or absence of reed - sternberg cells respectively ; there are multiple subtypes of each .
this patient presented with a dlbcl associated with chronic inflammation , and was ebv - positive .
the aetiology of anorectal abscess formation is wide ; ranging from infected anal glands ( cryptoglandular theory ) , inflammatory bowel disease ( including crohns ' disease ) , benign anal conditions ( e.g. fistula - in ano ) , as a complication of surgery , neoplasms and infection [ 4 , 5 ] reconstructing the anal canal and the sphincter following chemo - therapy remains a long - term option .
this will depend on residual muscle function   following treatment and the probability that the patient will remain in remission .
lymphomas presenting as abscesses have been described in patients with congenital or acquired states of immunodeficiency
. nevertheless , a high degree of suspicion must be present when a non - healing peri - anal abscess is encountered in an non - immune - compromised individuals .
the importance of good biopsy of tissue and histological surveillance in patients with non - resolving peri - anal conditions is vital .
 a non - healing peri - anal abscess can be difficult to manage and is often attributed to chronic disease . 
 this case documents a male in his seventh decade who presented with multiple peri - anal collections . 
 the abscess cavity had caused necrosis of the internal sphincter muscles resulting in faecal incontinence . 
 biopsies were conclusive for diffuse large b - cell lymphoma . 
 a de - functioning colostomy was performed and the patient was initiated on chop - r chemotherapy . 
 anal lymphoma masquerading as a peri - anal abscess is rare . 
 a high degree of suspicion must be maintained for an anal abscess which does not resolve with conservative management . 
INTRODUCTION
CASE REPORT
DISCUSSION