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Paper text:
mammary papillary lesions pose diagnostic challenges on fnac due to overlapping features of benign and malignant entities .
intracystic papillary carcinoma ( ipc ) is rare and characterized by a low - grade malignancy .
a 52-year - old male presented with chief complaints of swelling in the left breast for 3 years .
the swelling was sudden in onset and progressively increasing from the size of a peanut to its present size of a lemon .
, there was a subareolar swelling measuring 3 cm in diameter , which was nontender .
ultrasonography ( usg ) showed small ill - defined homogenous lesion measuring 2.9 cm  1.5 cm .
fnac from the swelling showed hypercellular smears with ductal epithelial cells arranged in papillae and glandular clusters [ figure 1a ] . at many places , cells had irregular nuclear membrane , prominent nucleoli , fine chromatin , scanty - to - moderate cytoplasm and high nuclear - cytoplasmic ratio .
the background showed abundant foamy macrophages , few naked bipolar nuclei , and necrotic debris [ figure 1b ] .
histopathology of the excised tissue showed well - circumscribed tumor nodule beneath the ulcerated skin .
the cells were arranged in a papillary pattern within a cystic space , with a central true fibrovascular core [ figure 1c ] .
the tumor cells showed multilayering , loss of polartiy , mild pleomorphism , and nuclear hyperchromasia [ figure 1d ] .
immunohistochemistry showed positivity for progesterone receptor ( pr ) and her2neu ; negativity for estrogen receptor ( er ) and s-100 markers .
systemic examination , chest x - ray , ultrasound liver , and bone scans did not show any evidence of metastases . ( a )
cytosmear showing papillary clusters ( pap stain 40 ) ( b ) smear showing atypical ductal cells with foamy macrophages ( lg 400 ) ( c ) section showing thick cyst wall with papillae ( h and e 40 ) ( d ) section showing tumor cells with pleomorphism ( h and e 100 ) photomicrographs of immunohistochemical markers showing ( a ) pr positivity ( ihc : pr 100 ) ( b ) her2neu positivity ( ihc : her2 neu 100 ) ( c ) er negativity ( ihc : er 100 ) ( d ) s-100 negativity ( ihc : s100 100 ) ( e ) ki-67 with focal positivity ( ihc : ki67 100 )
papillary lesions account for < 10% of benign and 0.5 - 2% of all malignant breast lesions .
ipc is usually seen in postmenopausal women aged 55 - 67 years with a higher median age at presentation in males .
clinically , it presents as a painless , firm subareolar mass or with a bloody nipple discharge , and at times remains asymptomatic .
grossly , it can be cystic or encapsulated with most lesions not demonstrating infiltrating margins .
papillary lesions of the breast encompass a complete spectrum including benign lesions ( papilloma ) to noninvasive ( intraductal papillary carcinoma ) to invasive papillary carcinomas .
noninvasive papillary carcinomas have two subtypes : the papillary variant of ductal carcinoma - in - situ and ipc . it is postulated that ipc arise in large central ducts and as the tumor develops , its secretions lead to cystic dilatation .
ipc is surrounded by a fibrous capsule and is characterized by a thin fibrovascular stalk devoid of a myoepithelial cell layer along with the presence of neoplastic cells of low - grade ductal carcinoma - in - situ ( dcis ) type .
it can be present as an isolated lesion or associated with nonpapillary dcis and/or invasive ductal carcinoma .
genetic alterations in the form of interstitial deletions and fusion of chromosome 16 and 1 ( 1;16 ) have been described .
the important differentials in males include gynecomastia , fibroadenoma , ductal carcinoma , and micropapillary carcimoma . in gynecomastia
, the smears may be hypercellular , with crowded but flattened epithelial and stromal fragments .
nuclear atypia may be present ; but , single epithelial cells and three - dimensional ( 3d ) clusters are almost absent , distinguishing it from a papillary lesion .
fibroadenomas are uncommon in males , and aspirates are hypercellular with flat branching sheets of benign ductal cells , stromal fragments , and bare nuclei .
invasive ductal carcinomas with focal papillary areas usually show high cellularity with complex crowded epithelial cells displaying nuclear atypia and absence of bare nuclei .
micropapillary carcinoma lacks true fibrovascular core and shows angulated papillary and tubuloalveolar pattern of cellular aggregates with single atypical cells .
smears from the ipc are highly cellular , composed predominantly of discohesive epithelial cells with minimal - to - mild cytological atypia .
variable pattern on immunohistochemistry for er , pr , her2neu , and androgen receptors have been reported by different authors . in the present case ,
ki-67 showed a low proliferative index with the presence of in - situ component and pushing borders rather than infiltrative .
few authors have demonstrated positivity for collagen iv , around the ipc , concluding that it is intraductal .
some pathologists now prefer the term  encapsulated papillary carcinoma  to the more traditional  intracystic papillary carcinoma .
 cytodiagnosis of ipc may at times be difficult since the smears may show presence of fibrosis , hemorrhage , or chronic inflammatory cells in the background .
aspiration of cyst fluid may dilute the cellularity , leading to errors in diagnosis . due to its indolent behavior on clinical and radiological examinations ,
usg reveals a hypoechoic area indicating the cyst with hyperechoes projecting from the cyst wall indicating the tumor part .
lesions tend to be well - defined on mammography . as per the recommendations of the world health organization ( who ) working group , treatment for ipc and dcis is the same .
in general , due to the low malignant potential and slow proliferative activity , prognosis of pure ipc is well - defined .
cytological diagnosis of ipc is difficult due to overlapping with benign entities and other mimics .
all lesions with papillary configuration fnac should be excised in total to be classified accurately .
papillary lesions of the breast pose great diagnostic challenges on fine needle aspiration cytology ( fnac ) due to overlapping features between benign and malignant entities . 
 preoperative cytodiagnosis is difficult . 
 we present a case of a 52-year - old male who presented with a progressively increasing firm swelling in the left breast for 3 years . 
 the nipple was eroded with ulceration and bleeding . 
 ultrasonography ( usg ) revealed a mass measuring 2.9 cm  1.5 cm in the left breast . 
 fnac smears were hypercellular with ductal cells arranged in papillae and glandular clusters . at places , the cells had irregular nuclear membrane , prominent nucleoli , fine chromatin , scanty - to - moderate cytoplasm , and high nuclear - cytoplasmic ratio with pleomorphism . 
 histopathology of the excised swelling was consistent with intracystic papillary carcinoma ( ipc ) supported with immunohistochemistry markers . 
 the case is being presented due to its rarity .