pseudovascular adenoid squamous cell carcinoma ( pascc ) is an uncommon histological variant of squamous cell carcinoma ( scc ) , characterized by acantholysis of the tumor cells , leading to the formation of anastomosing spaces and channels , mimicking an angiosarcoma . pascc has been reported in the head and neck , as well as in the other organs , such as the breast , lungs , urinary bladder , vulva , and uterine cervix . only two cases of pascc arising from the upper aerodigestive tract have been reported so far . a 40-year - old man presented to the department of ent with a fast - growing polypoid tumor on the right side floor of the mouth . wide excision of the tumor with right hemimandibulectomy and modified radical neck dissection was performed . on macroscopic examination , the right hemimandibulectomy specimen showed a polypoid mass measuring 6  6  3 cm at the right gingivo modified radical neck dissection showed 18 lymph nodes , largest measuring 1  1 cm , with gray - white to gray - brown areas . excised exophytic polypoid growth on the gingivo buccal sulcus on microscopic examination , the tumor was composed of vessel - like anastomosing channels , which were lined by a single layer of atypical epithelioid cells , along with dilated and congested blood vessels [ figures 2 and 3 ] . the lumina of these spaces contained pinkish material , few erythrocytes , and rare acantholytic tumor cells . seven out of 18 lymph nodes from modified radical neck dissection showed tumor deposits of similar looking cells . a differential diagnosis of scc and angiosarcoma was considered due to the presence of anastomosing channels of cells . vimentin showed focal positivity , but the tumor cells were negative for cd 34 [ figure 4 ] . hence , angiosarcoma was ruled out and a diagnosis of pascc [ t3n2m0 ] was made . ( a , b ) tumor with anastomosing vessel - like channels , lined by a single layer of malignant cells ( c , d ) showing tumor with dilated and congested blood vessels ( h and e , 100 ) ( a , b ) tumor showing areas of reactive fibrosis ; ( c ) tumor showing areas with acantholytic pattern ( h and e , 100 ) ; ( d ) lumina of pseudovascular spaces contain acantholytic tumor cells and erythrocytes ( h and e , 400 ) ( a ) immunohistochemical analysis showed tumor cells strongly positivity for cytokeratin ( b ) tumor cells are negative for cd34 variants of scc , which occur less frequently are verrucous carcinoma , spindle scc , papillary scc , basaloid scc , adenoid scc , lymphoepithelial carcinoma , and adenosquamous scc . their recognition is important because most of them are true clinicopathological entities , with an important prognostic implication . the adenoid form of scc is a neoplasm that is characterized by the fact that it presents a pseudoglandular pattern . the biological phenomenon that explains this histological pattern is acantholysis , which when massive may mimic a vascular proliferation and hence is known as pseudovascular adenoid scc . less than 30 cases of pascc in various sites have been documented in international literature so far . pascc has the clinical characteristics of scc , but histologically may mimic an angiosarcoma . interestingly in the oral cavity , the peak incidence of angiosarcoma is in the 7 decade and that of pascc is in the 6 decade . macroscopically , both these entities are seen as fast - growing eruptive lesions in the oral cavity and have a poor prognosis . histologically , angiosarcoma consists of interanastomosing vascular spaces lined by malignant cells , which are spindle shaped or epithelioid in shape ; whereas , in pascc , massive acantholysis in the tumor gives the appearance of pseudovascular spaces . occasionally , reactive fibrosis within the tumor , superimposed upon the acantholytic pattern , results in artifactual clefts lined by poorly differentiated malignant cells , creating an angiomatous appearance . fanberg - smith et al . in their study found that one - third of oral angiosarcomas were of the epithelioid type , which may be mistaken for other epithelioid tumors . immunohistochemistry is very helpful in differentiating both these entities , because the epidermoid differentiation in pascc may be extremely masked by pseudovascular proliferation . with the onset of cytological techniques , the correct identification of pascc and aspiration of pascc yields individually scattered and syncytial fragments of malignant epithelioid appearing cells with oval to spindle shapes , prominent nucleoli , and a finely vacuolated amphophilic cytoplasm . malignant cells are seen singly and in clusters or arranged in tight aggregates , loose groups , and parallel bundles of streaming malignant cells resembling abortive capillaries . a careful search will reveal the association of malignant cells with vascular lumina , indicating their endothelial origin . in the absence of these vasoformative structures , ancillary immunohistochemical studies and clinical history are essential in such cases to arrive at a correct diagnosis . on immunohistochemistry , pascc will usually express epithelial markers such as cytokeratin and epithelial membrane antigens , whereas angiosarcoma typically expresses vascular antigens cd 31 , cd 34 , and von willebrand factor , which are not expressed in adenoid scc . recently , fli-1 protein , a member of the ets family of dna binding transcription factors , has been highlighted as a new vascular differentiation marker , which is positive in angiosarcoma . another new marker , laminin-5 , was found to be positive in the cytoplasm of pascc cells and negative in angiosarcoma . acantholysis is suggested to be the underlying pathogenetic mechanism , possibly as a consequence of changes in adhesion molecule expression by the tumor cells . this can be observed as loss of expression of adhesion molecule e- cadherin , which is one of the major adhesion molecules on the epithelial cells . cadherin complex , which is present on the cell membrane and which mediates cell - to - cell adhesion , is obviously disturbed in pascc and this is responsible for forming of typical intercellular spaces . studies have shown that e- cadherin is expressed in most scc in the head and neck , the expression being strong in well - differentiated cancers , but reduced in poorly differentiated tumors . pascc is almost always accompanied by foci of conventional scc , suggesting the correct diagnosis . the problem arises in biopsies , when the presence of a pseudovascular component only may be misinterpreted as an angiosarcoma . in the present case , biopsy was suggestive of a moderately differentiated scc , whereas the tumor itself showed features of pascc , thus simulating a vascular neoplasm . but a review of the biopsy , along with immunohistochemistry of the tumor proper , helped us to come to the correct diagnosis . the etiology and prognosis of pascc are probably similar to adenoid scc than conventional scc . but the number of patients reported so far is too small to draw firm conclusions . in conclusion , although the prognostic importance of pascc in the head and neck is still ill understood , its recognition is important because it may mimic angiosarcoma , which may result in erroneous treatment .
pseudovascular adenoid squamous cell carcinoma ( pascc ) is an uncommon histological variant of squamous cell carcinoma that can mimic vascular neoplasms , particularly angiosarcoma , in its morphologic characteristics . 
 pascc has been reported in the head and neck , as well as in the other organs such as the breast , lungs , urinary bladder , vulva , and uterine cervix . 
 only two cases of pascc arising from the upper aerodigestive tract have been reported so far . 
 we report a case of pascc of oral cavity in a 40-year - old man , which mimicked an angiosarcoma initially . 
 immunohistochemical analysis led to a conclusive diagnosis of pascc .