Pseudoangiosarcomatous Squamous Cell Carcinoma of Skin Arising Adjacent to Decubitus Ulcers

Metastatic squamous cell carcinoma with pseudoangiosarcomatous features and aberrant expression of vascular markers

Squamous cell carcinoma with pseudoangiosarcomatous features is a rare but well-recognized variant of squamous cell carcinoma. These tumors exhibit complex anastomosing channels lined by neoplastic cells, histologically mimicking a vasoformative mesenchymal tumor. Immunohistochemically, the published cases expressed epithelial markers and were consistently negative for vascular markers. Squamous cell carcinoma with pseudoangiosarcomatous features and aberrant expression of vascular markers has never been reported. Herein, we report two cases of metastatic poorly-differentiated squamous cell carcinoma with pseudoangiosarcomatous morphologic features which showed immunoreactivity for vascular markers (CD31, Fli-1, and ERG). One case (left thigh skin squamous cell carcinoma with abdominal wall metastasis) showed strong and diffuse positivity for vascular markers, and the final diagnosis was confirmed with electron microscopy. The second case (squamous cell carcinoma of unknown primary site with bone metastasis) showed patchy positivity for both squamous and vascular markers. This is the first report of squamous cell carcinoma with pseudoangiosarcomatous features and aberrant expression of vascular markers, which resembles angiosarcoma both morphologically and immunohistochemically, and may represent a potential diagnostic pitfall. It is of crucial importance for pathologists to be aware of metastatic squamous cell carcinoma with such unique features, so that misdiagnosis and inappropriate treatment will be avoided.

Pseudoangiosarcomatous squamous cell carcinoma developing on a burn scar: a case report and review of the literature

Pseudoangiosarcomatous squamous cell carcinoma, also known as pseudovascular, pseudovascular adenoid and pseudoangiomatous squamous cell carcinoma, is an exceedingly rare, aggressive variant of cutaneous squamous cell carcinoma with extreme acantholysis resulting in angiosarcoma-like areas. Histologically, a pseudoangiosarcomatous pattern includes complex anastomosing channels and spaces lined with neoplastic cells. The neoplastic cells exhibit cytokeratin and vimentin positivity but yield negative results with CD31 and CD34. This case report describes pseudoangiosarcomatous squamous cell carcinoma developing on a burn scar on the ankle. In this report, we emphasize the importance of establishing a diagnosis with histological and immunohistochemical examination, and we review the described incidence of the age and sites with the prognosis for the treatment of pseudoangiosarcomatous squamous cell carcinoma of the skin.

Pseudoangiosarcomatous squamous cell carcinoma of the lung

Pulmonary pseudoangiosarcomatous squamous cell carcinoma (PSCC) is a rare aggressive variant of squamous cell carcinoma. Histopathologically, PSCC is characterized by interanastomosing cords and channels, lined by atypical cells, with spaces containing erythrocytes or floating tumour cells. PSCC mimics angiosarcoma, so careful attention should be paid to immunohistochemical differences. Two PSCC cases are described here: in a 79-year-old male, bronchoscopy revealed mucosal swelling and hypertrophy and an adrenal mass was found 1 month later; in a 76-year-old male, computed tomography revealed rib destruction due to a non-calcified soft-tissue tumour and, although the tumour resembled an angiosarcoma, endothelial markers were negative and cytokeratin and p63 markers were positive. Immunohistochemical analyses may be helpful in establishing an accurate diagnosis. PSCC had a progressive course in both patients, who died ≤ 3 months postdiagnosis.

Pseudoangiomatous Squamous Cell Carcinoma in the Oral Cavity of a Dog

An 8-year-old, spayed, female Labrador Retriever mixed-breed dog was presented to the Cornell University Hospital for Animals with an invasive oral mass involving the upper left fourth premolar and first molar teeth. Initial biopsy results suggested a poorly differentiated squamous cell carcinoma, whereas further histologic examination of the surgically removed mass revealed a hemangiosarcoma-like mass composed of numerous vascular clefts and variable numbers of keratinizing epithelial cells. Histologic and immunohistochemical characteristics were compatible with pseudoangiomatous squamous cell carcinoma, a well-recognized human variant of acanthomatous squamous cell carcinoma. Because of histomorphologic similarities with canine gingival hemangiosarcoma, diagnosticians should be aware of the present tumor variant as a differential diagnosis for vascular-like growths in the oral cavity of dogs.

Pseudovascular adenoid squamous-cell carcinoma of the oral cavity--a report of two cases

Informed consent was obtained for the publication of the patients' details in this report. Two cases of pseudovascular adenoid squamous-cell carcinoma (SCC) in the oral cavity are described, which were characterised by acantholysis of the tumour cells, with formation of anastomosing spaces and channels mimicking an angiosarcoma. Both tumours contained foci of SCC suggesting the correct diagnosis: in one patient conventional SCC, and in the other, a spindle-cell carcinoma. The pathogenesis of pseudovascular adenoid SCC is unknown. Our cases were characterised by loss of immunohistochemical expression of E-cadherin, one of the major adhesion molecules of epithelial cells. Pseudovascular adenoid SCC is suggested to be pathogenetically related to the loss of E-cadherin expression, leading to the loss of tumour cell-cell adhesion.

[Pseudovascular squamous cell carcinoma]

The adenoid form of squamous cell carcinoma is a neoplasm that is characterized by the fact that it presents a pseudoglandular pattern in the histological study. The biological phenomenon that explains this histological pattern is acantholysis; when the latter is massive, the tumor may even mimic a vascular proliferation, and is known as pseudovascular squamous cell carcinoma. This tumor has the clinical characteristics of a squamous cell carcinoma, but histologically, it may mimic an angiosarcoma. Most cases of pseudovascular squamous cell carcinoma of the skin have a poor prognosis.