primary intracystic squamous cell carcinoma ( scc ) in the breast is an extremely rare neoplasm .
primary sccs in the breast are quite rare , although scc mixed with ductal carcinoma is more common .
it can arise from metaplastic epithelium associated with other primary malignancy of the breast , metastasis from primary elsewhere in the body or an extension of malignancy from the skin covering .
a 45-year - old female presented with a lump in the right breast , which she had noticed since three weeks .
her menstrual cycles were regular and she had two children . clinical examination revealed a firm cystic lump of 12  10 cm in the upper inner and central quadrant of the right breast .
the skin over the right breast appeared stretched , with a slight retraction of the nipple .
pre - operatively , the patient was relegated to clinical stage iii ( t3n0m0 ) .
ultrasonographic examination of the right breast showed an irregular - shaped hypoechoic lesion measuring 12  6 cm with an internal anechoic area measuring 6  3 cm , suggesting a cystic malignant tumor .
fine needle aspiration from the lump in the right breast yielded 10 ml of pale yellow serous fluid .
wet - fixed and air - dried smears were prepared from the centrifuged aspirated fluid and were stained with papanicolaou ( pap ) stain and may - grnwald - giemsa ( mgg ) stain , respectively .
the smears studied were cellular and showed malignant squamous cells predominantly in singles and occasional syncytial groups , and some cells were spindle shaped .
the malignant squamous cells had rounded borders with hyperchromatic enlarged nucleus and coarse irregular granular chromatin .
cytoplasm of the squamous cells showed a variable degree of keratinisation [ figure 2 ] .
cytology smears showing malignant squamous cells in singles with numerous cyst macrophages ( mgg , 400 ) cytology smear showing malignant squamous cells in singles , demonstrating cytoplasmic keratinisation ( pap , 400 ) to exclude metastatic scc , a search for remote primary scc included chest radiograph , cystoscopy , colposcopy , oesophagogastroscopy , laryngoscopy and cervical pap smear , which did not reveal any extramammary cancer .
the criteria include : ( 1 ) no other neoplastic element , such as ductal or mesenchymal ones , are present in the tumor , ( 2 ) the tumor is independent of adjacent cutaneous structures and ( 3 ) no other distant epidermoid tumor exists in the patient . later , simple mastectomy with axillary clearance was performed and the specimen was sent for histological examination .
the cut - section of the mastectomy specimen showed a large cystic tumor measuring 8  3 cm , containing yellow serous fluid .
the cystic cavity was lined by dysplastic squamous epithelium with an infiltrating tumor , showing malignant squamous cells in broad sheets , groups and whorls , with keratin - pearl formation and intercellular bridges .
immunostaining for estrogen / progesterone receptor and her-2/neu oncoprotein were negative and that for cytokeratin was positive .
the smears studied were cellular and showed malignant squamous cells predominantly in singles and occasional syncytial groups , and some cells were spindle shaped .
the malignant squamous cells had rounded borders with hyperchromatic enlarged nucleus and coarse irregular granular chromatin .
cytoplasm of the squamous cells showed a variable degree of keratinisation [ figure 2 ] .
cytology smears showing malignant squamous cells in singles with numerous cyst macrophages ( mgg , 400 ) cytology smear showing malignant squamous cells in singles , demonstrating cytoplasmic keratinisation ( pap , 400 ) to exclude metastatic scc , a search for remote primary scc included chest radiograph , cystoscopy , colposcopy , oesophagogastroscopy , laryngoscopy and cervical pap smear , which did not reveal any extramammary cancer .
the criteria include : ( 1 ) no other neoplastic element , such as ductal or mesenchymal ones , are present in the tumor , ( 2 ) the tumor is independent of adjacent cutaneous structures and ( 3 ) no other distant epidermoid tumor exists in the patient . later , simple mastectomy with axillary clearance was performed and the specimen was sent for histological examination .
the cut - section of the mastectomy specimen showed a large cystic tumor measuring 8  3 cm , containing yellow serous fluid .
multiple sections studied showed cystic breast tumor . the cystic cavity was lined by dysplastic squamous epithelium with an infiltrating tumor , showing malignant squamous cells in broad sheets , groups and whorls , with keratin - pearl formation and intercellular bridges .
immunostaining for estrogen / progesterone receptor and her-2/neu oncoprotein were negative and that for cytokeratin was positive .
pure scc and adenosquamous carcinoma have been listed under metaplastic breast carcinomas in the world health organization classification .
the japanese breast cancer society has defined  scc of the breast as a special type of cancer , in which malignant cells are arranged in broad sheets and whorls with keratin formation or intercellular bridge  .
the incidence of scc reported in the western countries is 0.13.6% and in japan , it is 0.17% .
the age group affected is between 32 and 65 years , with an increased tendency of left - sided involvement .
the characteristics of scc of the breast generally reported are a large - sized tumor , rapidly growing with a central cyst formed by necrosis .
this is unlikely in our case because there was little necrosis elsewhere in the tumor .
the possible mode of origin of scc is epidermoid cyst of the breast , chronic abscess and complete metaplasia of glandular breast tissue .
lymph node involvement is reported to be less frequent than might be expected , given the larger tumor size .
the tumor cells are negative for vimentin , estrogen and progesterone and are diffusely positive for high molecular weight cytokeratin and c - erbb-2 . squamous cells in fine needle aspiration cytology ( fnac ) of breast lesions can be found in various benign lesions , like epidermoid cyst , subareolar abscess , fibroadenoma , infracted papillomas , spindle cell metaplasia , cystic sarcoma phyllodes , pseudosarcoma and malignant breast tumors or metastatic malignancy
. the benign breast conditions with abundant squamous cells may sometimes mimic malignant squamous lesion and vice versa . in general
benign squamous cells are bland looking and are often associated with anucleated squames , and no tumor , cell cannibalism .
the malignant squamous cells are more pleomorphic , mitotically active and dyskeratotic and , sometimes , bizarre - shaped cells can be seen .
the differential diagnosis of malignant squamous cells in fnac of the breast includes primary scc and metastatic scc of the breast .
careful assessment of cytological features of squamous cells and the background appearance appears to be critical for arriving at a correct diagnosis .
however , in the case of intracystic scc , numerous foamy macrophages coexist with malignant squamous cells .
hormonal therapy is not indicated as most cases of scc are negative for hormonal receptors .
scc of the breast is reported to be resistant to both radiotherapy and standard chemotherapy performed for invasive ductal carcinoma . in our case ,
radical mastectomy with axillary clearance was performed with postoperative adjuvant therapy , as given for common types of breast cancers .
there was no evidence of recurrence of the tumor after four years of treatment . in conclusion ,
the presence of malignant squamous cells in fine needle aspiration of the breast suggests primary scc or metastatic scc .
the finding of a pure scc necessitates more accurate work - up to exclude skin lesion or metastasis .
the primary scc should not be confused with a much more largely manifested metaplastic change in other usual breast cancers .
although the presence of numerous cyst macrophages in the background of breast fnac smears suggests a benign lesion , when present with malignant squamous cells , they suggest intracystic scc .
 primary intracystic squamous cell carcinoma ( scc ) of the breast is an extremely rare entity and has a low incidence in comparison with other breast cancers . 
 we report a rare case of primary intracystic scc in a 45-year - old woman who presented with a cystic lump in the right breast . 
 cytological smears of the fluid aspirated from the breast tumor revealed malignant squamous cells dispersed in single and occasional groups along with numerous cyst macrophages , suggesting cystic scc . 
 histological study of the mastectomy specimen confirmed the diagnosis of primary intracystic scc . 
 although the presence of abundant foamy macrophages in the background of fine needle aspiration cytology smears of the breast suggest benign breast lesion , when associated with malignant squamous cells , these suggest cystic primary scc or metastatic scc . 
 the primary scc should not be confused with metaplastic change in other breast carcinomas . 
Introduction
Case Report
Cytology
Histology
Discussion