Spindle cell neoplasms coexpressing cytokeratin and vimentin (metaplastic squamous cell carcinoma)

Tumour Recurrence, Depth of Invasion, and Temple Location as Independent Prognostic Parameters of Lymph Node Metastases of Head and Neck Cutaneous Squamous Cell Carcinomas

The excellent survival rate of cutaneous squamous cell carcinoma (cSCC) exceeding 90% is reduced by the presence of nodal metastases by over 50%. We analysed various risk parameters of cSCC to predict the incidence of nodal metastases. A total of 118 patients with the head cSCC were included in a single-institution retrospective study covering the period from 2008 to 2020. Tumour recurrence, temple location, and tumour infiltration depth were found to be independent predictors of nodal metastases (increasing the probability of metastases by 8.0, 8.1, and 4.3 times, respectively). Furthermore, univariate analysis shows that the tumour size and T stage are significant factors increasing the risk of metastases. Several independent risk factors for the development of metastases in the head cSCC have been confirmed. These findings might help identify at-risk patients who require additional attention for adequate radical treatment and close follow-up. In contrast, elective treatment of lymph nodes is not recommended due to the low incidence of regional metastases.

Pitfalls and Caveats in Applying Chromogenic Immunostaining to Histopathological Diagnosis

Chromogenic immunohistochemistry (immunostaining using an enzyme-labeled probe) is an essential histochemical technique for analyzing pathogenesis and making a histopathological diagnosis in routine pathology services. In neoplastic lesions, immunohistochemistry allows the study of specific clinical and biological features such as histogenesis, behavioral characteristics, therapeutic targets, and prognostic biomarkers. The needs for appropriate and reproducible methods of immunostaining are prompted by technical development and refinement, commercial availability of a variety of antibodies, advanced applicability of immunohistochemical markers, accelerated analysis of clinicopathological correlations, progress in molecular targeted therapy, and the expectation of advanced histopathological diagnosis. However, immunostaining does have various pitfalls and caveats. Pathologists should learn from previous mistakes and failures and from results indicating false positivity and false negativity. The present review article describes various devices, technical hints, and trouble-shooting guides to keep in mind when performing immunostaining.

A multifaceted investigation into molecular associations of chronic thromboembolic pulmonary hypertension pathogenesis

Purpose

Chronic thromboembolic pulmonary hypertension is characterized by incomplete thrombus resolution following acute pulmonary embolism, leading to pulmonary hypertension and right ventricular dysfunction. Conditions such as thrombophilias, dysfibrinogenemias, and inflammatory states have been associated with chronic thromboembolic pulmonary hypertension, but molecular mechanisms underlying this disease are poorly understood. We sought to characterize the molecular and functional features associated with chronic thromboembolic pulmonary hypertension using a multifaceted approach.

Methods

We utilized functional assays to compare clot lysis times between chronic thromboembolic pulmonary hypertension patients and multiple controls. We then performed immunohistochemical characterization of tissue from chronic thromboembolic pulmonary hypertension, pulmonary arterial hypertension, and healthy controls, and examined RNA expression patterns of cultured lymphocytes and pulmonary arterial specimens. We then confirmed RNA expression changes using immunohistochemistry, immunofluorescence, and Western blotting in pulmonary arterial tissue.

Results

Clot lysis times in chronic thromboembolic pulmonary hypertension patients are similar to multiple controls. Chronic thromboembolic pulmonary hypertension endarterectomized tissue has reduced expression of both smooth muscle and endothelial cell markers. RNA expression profiles in pulmonary arteries and peripheral blood lymphocytes identified differences in RNA transcript levels related to inflammation and growth factor signaling, which we confirmed using immunohistochemistry. Gene expression data also suggested significant alterations in metabolic pathways, and immunofluorescence and Western blot experiments confirmed that unglycosylated CD36 and adiponectin expression were increased in chronic thromboembolic pulmonary hypertension versus controls.

Conclusions

Our data do not support impaired clot lysis underlying chronic thromboembolic pulmonary hypertension, but did demonstrate distinct molecular patterns present both in peripheral blood and in pathologic specimens of chronic thromboembolic pulmonary hypertension patients suggesting that altered metabolism may play a role in chronic thromboembolic pulmonary hypertension pathogenesis.

Genome-wide methylation profiling and copy number analysis in atypical fibroxanthomas and pleomorphic dermal sarcomas indicate a similar molecular phenotype

Background

Atypical fibroxanthomas (AFX) and pleomorphic dermal sarcomas (PDS) are lesions of the skin with overlapping histologic features and unspecific molecular traits. PDS behaves aggressive compared to AFX. Thus, a precise delineation, although challenging in some instances, is relevant.

Methods

We examined the value of DNA-methylation profiling and copy number analysis for separating these tumors. DNA-methylation data were generated from 17 AFX and 15 PDS using the Illumina EPIC array. These were compared with DNA-methylation data generated from 196 tumors encompassing potential histologic mimics like cutaneous squamous carcinomas (cSCC; n = 19), basal cell carcinomas (n = 10), melanoma metastases originating from the skin (n = 11), leiomyosarcomas (n = 11), angiosarcomas of the skin and soft tissue (n = 11), malignant peripheral nerve sheath tumors (n = 19), dermatofibrosarcomas protuberans (n = 13), extraskeletal myxoid chondrosarcomas (n = 9), myxoid liposarcomas (n = 14), schwannomas (n = 10), neurofibromas (n = 21), alveolar (n = 19) and embryonal (n = 17) rhabdomyosarcomas as well as undifferentiated pleomorphic sarcomas (n = 12).

Results

DNA-methylation profiling did not separate AFX from PDS. The DNA-methylation profiles of the other cases, however, were distinct from AFX/PDS. They reliably assigned to subtype-specific DNA-methylation clusters, although overlap occurred between some AFX/PDS and cSCC. Copy number profiling revealed alterations in a similar frequency and distribution between AFX and PDS. They involved losses of 9p (22/32) and 13q (25/32). Gains frequently involved 8q (8/32). Notably, a homozygous deletion of CDKN2A was more frequent in PDS (6/15) than in AFX (2/17), whereas amplifications were non-recurrent and overall rare (5/32).

Conclusions

Our findings support the concept that AFX and PDS belong to a common tumor spectrum. We could demonstrate the diagnostic value of DNA-methylation profiling to delineating AFX/PDS from potential mimics. However, the assessment of certain histologic features remains crucial for separating PDS from AFX.

Primary Cutaneous Spindle Cell Squamous Carcinoma Expressing Smooth Muscle Actin: Diagnostic Pitfalls

Alpha smooth muscle actin (SMA) belongs to the actin proteins. It is a known immunohistochemical marker for tumors of mesenchymal origin. There have been reports of expression of SMA in certain epithelial malignancies in the head and neck and genital regions. In this study, the authors report a primary cutaneous spindle cell squamous carcinoma expressing SMA. Both high- and low-molecular-weight keratins and p63 were positive, and S100 protein, SOX10, MART-1/Melan-A, and muscle-specific actin stains were negative. This case highlights that an epithelial tumor could express a mesenchymal marker, thereby making the diagnosis problematic.

Histology of Non-Melanoma Skin Cancers: An Update

Non-melanoma skin cancer (NMSC) is the most frequently diagnosed cancer in humans. Several different non-melanoma skin cancers have been reported in the literature, with several histologic variants that frequently cause important differential diagnoses with other cutaneous tumors basal cell carcinoma (BCC) is the most common malignant skin tumor, with different histologic variants that are associated with a greater or less aggressive behavior and that usually may be confused with other primitive skin tumors. Actinic keratosis, Bowen’s disease, keratoacanthoma, and invasive squamous cell carcinoma (SCC) correspond to the other line of NMSC, that may have only local tumoral behavior, easy to treat and with local management (as in the case of actinic keratosis (AK), Bowen’s disease, and keratoacanthoma) or a more aggressive behavior with a potential metastatic spread, as in case of invasive SCC. Therefore, histopathology serves as the gold standard during daily clinical practice, in order to improve the therapeutical approaches to patients with NMSC and to understand the distinct histopathological features of NMSC. Here, we reported the main pathological features of different non-melanoma skin cancers.

Combined Merkel Cell Carcinoma and Atypical Fibroxanthoma

Background:

Although there are reports of squamous cell carcinoma arising within and adjacent to Merkel cell carcinoma, and one report of an atypical fibroxanthoma-like tumor arising in an irradiated recurrent Merkel cell carcinoma, there have previously been no reports of an immunohistochemically verified atypical fibroxanthoma occurring in conjunction with a Merkel cell carcinoma.

Objective:

We report on a neoplasm with distinct features of both Merkel cell carcinoma and atypical fibroxanthoma.

Methods:

Histologic and immunohistochemical evaluations were performed.

Results:

Our results verify the finding of a combined Merkel cell carcinoma and atypical fibroxanthoma.

Conclusion:

This case is an interesting and unusual combination of tumors. The origin of the Merkel cell carcinoma is revisited. Debated origins include neuroendocrine, epithelial, and pleuripotent stem cell.

A Case of Solitary Nonvascularized Corneal Epithelial Dysplasia

Background. Epithelial dysplasia is categorized as conjunctival/corneal intraepithelial neoplasia which is a precancerous lesion. The lesion is usually developed at the limbal region and grows towards central cornea in association with neovascularization into the lesion. Here, we report a case of isolated nonvascularized corneal epithelial dysplasia surrounded by normal corneal epithelium with immune histochemical finding of ocular surface tissues cytokeratins, for example, keratin 13 and keratin 12. Case Presentation. A 76-year-old man consulted us for visual disturbance with localized opacification of the corneal epithelium in his left eye. His visual acuity was 20/20 and 20/200 in his right and left eye, respectively. Slit lamp examination showed a whitish plaque-like lesion at the center of his left corneal epithelium. No vascular invasion to the lesion was found. The lesion was surgically removed and subjected to histopathological examination and diagnosed as epithelial dysplasia. Amyloidosis was excluded by direct fast scarlet 4BS (DFS) staining. Immunohistochemistry showed that the dysplastic epithelial cells express keratin 13 and vimentin, but not keratin 12, indicating that the neoplastic epithelial cells lacked corneal-type epithelium differentiation. Conclusions. The lesion was diagnosed as nonvascularized epithelial dysplasia of ocular surface. Etiology of the lesion is not known.

Atypical Fibroxanthoma: A case series and review of literature

INTRO/OBJECTIVE

Atypical Fibroxanthoma (AFX) is a rare cutaneous neoplasm arising from myofibroblast or fibroblast-like cells that predominantly affects the head and neck region. It commonly mimics more invasive neoplasms and is a diagnostic challenge to clinicians. The aim of this study was to develop a better understanding of AFX, focusing on recent developments in diagnosis and management.

METHODS

A retrospective case series and review of recent literature were carried out.

RESULTS

Over a 17-year period, seven cases were identified (six male, mean age at presentation was 75.9 years). Two patients underwent complete excision and five patients had curettage and cauterisation. Two patients developed local recurrence but none demonstrated signs suggestive of metastatic spread. Histologically all seven lesions displayed a spindle cell pattern. Where performed, immunohistochemical staining was positive for Vimentin, CD10, CD68 and actin, and negative for CAM 5.2, CD34, Melan-A, S100 protein, HMB45, Cytokeratin A1/A3.

CONCLUSION

Our patient demographics, histopathology and immunohistochemistry are comparable to previous studies. Although advances have been made in immunohistochemical analysis, we are yet to discover a specific diagnostic immunostain for AFX. Clinical findings should therefore be correlated with histology and a panel of immunohistochemical stains should be used. Given the potential for recurrence or metastases, Moh's Micrographic Surgery with regular follow-up may be the preferred management.

Spindle Cell Squamous Cell Carcinoma Showing Continuous Mesenchymal Dedifferentiation in a Single Tumor

We report the case of an 85-year-old man who presented with an enlarging tumor on the right temple. Histologically, spindle-shaped cells were proliferating continuously within well-differentiated squamous cell carcinoma that was immunohistochemically negative for vimentin and alpha-smooth muscle actin (ASMA) but positive for cytokeratin (AE1/3). These spindle-shaped cells expressed vimentin and ASMA but not cytokeratin (AE1/3). Intermediate cells with round nuclei and small amounts of cytoplasm displayed slight expression of vimentin, ASMA, and cytokeratin. This case illustrated spindle cell squamous cell carcinoma with mesenchymal metaplasia of malignant epithelial cells.

Atypical fibroxanthoma: new insights

Atypical fibroxanthoma (AFX) is an ultraviolet radiation-associated dermal neoplasm. To address the clinicopathologic and molecular features of this particular neoplasm. The author conducted a literature review using PubMed searching for articles relating to AFX. AFX usually appears as a rapidly growing nodular or nodulo-ulcerative lesion. It occurs on sun-exposed skin of elderly peoples. AFX may be composed predominantly of pleomorphic, spindle, epithelioid cells, or admixture of these cells. The differential diagnosis of AFX includes pleomorphic dermal sarcoma, squamous cell carcinoma, malignant melanoma and leiomyosarcoma. Several observations favor a mesenchymal origin for AFX. These reviews address the clinicopathologic features, molecular pathology, prognosis and treatment of this neoplasm.

Cutaneous squamous cell carcinoma of the head and neck

Cutaneous squamous cell carcinoma of the head and neck is an epidemic that reaches all parts of the world. Making the diagnosis relies on the acumen of the clinician and pathologist. Various pathologic subtypes exist and differ in histology and prognosis. High-risk tumors need aggressive treatment and vigilant surveillance to monitor for recurrence. Large tumors, deep tissue invasion, perineural involvement, recurrence, location in high-risk areas, and immunosuppression are implicated in worsening prognosis. Surgery is the mainstay of treatment with adjuvant radiation therapy as needed for aggressive tumors; however, other modalities are potentially useful for low-risk lesions. The use of Mohs surgery has become increasingly useful and has shown high success rates. Involvement of parotid and neck lymph nodes significantly affects outcomes and the physician should be comfortable with management of this complex disease. This paper examines the diagnosis, pathology, clinical course, and treatment options for cutaneous squamous cell carcinoma of the head and neck.

Immunohistochemical distinction of cutaneous spindle cell carcinoma

Cutaneous spindle cell squamous carcinoma is an uncommon variant of squamous cell carcinoma in which keratinocytes infiltrate the dermis as single cells with elongated nuclei rather than as cohesive nests or islands, and signs of keratinization of conventional squamous cell carcinoma are insubstantial or nonexistent. Spindle cell carcinoma must be distinguished from spindle cell/desmoplastic melanoma, cutaneous leiomyosarcoma, atypical fibroxanthoma (AFX), and scar. In instances when there is no definitive evidence of squamous differentiation, immunohistochemical studies may confer diagnostic discrimination. Twenty-four cases consisting of 12 spindle cell squamous cell carcinomas, 3 AFXs, 3 leiomyosarcomas, 3 desmoplastic melanomas, and 3 scars were evaluated with a battery of immunohistochemical stains, with the specificity and sensitivity of each marker calculated. The immunohistochemical battery consisted of S-100, desmin, CD68, and smooth muscle actin and cytokeratins P KER (keratins predominantly of molecular weight 56 and 69 kd) and low-molecular weight keratin (CAM 5.2), AE1/AE3, p63, and 34 beta E12 (CK903). Spindle cell squamous carcinomas were negative for S-100, CD68, smooth muscle actin, and desmin with the exception of 2 cases with weak staining for smooth muscle actin. 34 beta E12 provided positive results for each spindle cell squamous carcinoma. The other cytokeratin stains were less sensitive for spindle cell squamous carcinoma than 34 beta E12. The final immunohistochemical results were as follows: 34 beta E12 (12/12, 100%), p63 (10/12, 80%), AE1/AE3 (8/12, 67%), low-molecular weight keratin (7/12, 58%), and P KER (4/12, 33%). The 3 AFXs were positive for CD68 and negative for all other stains, whereas the 3 leiomyosarcomas stained positively for desmin and smooth muscle actin and negatively for all other stains. The 3 melanomas stained positively for S-100 and negatively for all other immunohistochemistry. The scars were negative for all stains. In conclusion, our study of 34 beta E12 proved most promising in distinguishing spindle cell squamous carcinoma from the histologic mimickers, AFX, spindle cell melanoma, scar, and leiomyosarcoma.

p63 is a useful marker for cutaneous spindle cell squamous cell carcinoma

BACKGROUND

Cutaneous spindle cell squamous cell carcinoma (SCSCC) is a rare variant of SCC. This lesion is sometimes difficult to diagnose based purely on morphologic features. p63 is a member of the p53 gene family that can be identified in epithelial malignancies.

METHODS

Thirteen cases of spindle SCC were stained with p63, CK34betaE12, MNF116, vimentin, and S100. Control cases included desmoplastic melanoma (eight cases), atypical fibroxanthoma (AFX) (10 cases), dermatofibrosarcoma protuberans (eight cases), and cutaneous leiomyosarcoma (LMS) (four cases).

RESULTS

p63 was expressed diffusely in the nuclei of 100% (13/13) of SCSCCs. Of controls, p63 showed focal labeling of two LMS and two AFX. MNF116 and CK34betaE12 were positive in 13/13 SCSCCs. Of controls, one LMS was focally positive for MNF116. All SCSCCs and all control cases were positive for vimentin.

CONCLUSIONS

In the given differential diagnosis, p63 appears relatively specific to SCSCC and adds a useful nuclear marker to the available repertoire. The findings also suggest that cytokeratins MNF116 and CK34betaE12 may be more useful than standard cytokeratins in labeling SCSCC.

Combined Merkel Cell Carcinoma and Atypical Fibroxanthoma

BACKGROUND

Although there are reports of squamous cell carcinoma arising within and adjacent to Merkel cell carcinoma, and one report of an atypical fibroxanthoma-like tumor arising in an irradiated recurrent Merkel cell carcinoma, there have previously been no reports of an immunohistochemically verified atypical fibroxanthoma occurring in conjunction with a Merkel cell carcinoma.

OBJECTIVE

We report on a neoplasm with distinct features of both Merkel cell carcinoma and atypical fibroxanthoma.

METHODS

Histologic and immunohistochemical evaluations were performed.

RESULTS

Our results verify the finding of a combined Merkel cell carcinoma and atypical fibroxanthoma.

CONCLUSION

This case is an interesting and unusual combination of tumors. The origin of the Merkel cell carcinoma is revisited. Debated origins include neuroendocrine, epithelial, and pleuripotent stem cell.

Cutaneous carcinosarcoma: adnexal vs. epidermal types define high- and low-risk tumors. Results of a meta-analysis

OBJECTIVE

We report four cases of cutaneous carcinosarcoma (CS) and perform a meta-analysis of the cutaneous CS literature.

RESULTS

CS occurred in elderly patients (mean of 80 years) on sun-damaged skin, and were keratotic papules of short duration. They did not recur after excision. CS exhibited basal cell carcinoma mixed with atypical fibroxanthoma cell populations. Immunophenotyping revealed vimentin+/keratin- spindle cells and vimentin-/keratin+ epithelial cells. Three cases exhibited p53 protein expression of both carcinomatous and sarcomatous components. Literature review identified 38 cases of cutaneous CS that could be broadly classified into two distinct groups. Epidermal-derived (basal or squamous cell carcinoma epithelial component) CS arose on the sun-damaged skin of the head and neck of elderly males (mean age 72 years) and had a 70% 5-year disease-free survival. In contrast, adnexal CS (spiradenocarcinoma, porocarcinoma, proliferating tricholemmal cystic carcinoma, or matrical carcinoma) occurred in younger patients (mean age 58 years), showed recent growth in a long-standing nodule and had a 25% 5-year disease-free survival. Age less than 65 years, recent growth, long-standing skin tumor, and tumor size greater than 2 cm significantly correlated with poor outcome.

CONCLUSIONS

Cutaneous CS is an aggressive skin cancer with high risk for advanced disease. Significant risk factors exist whose identification will allow for better management of CS patients.

Cutaneous Spindle Cell Carcinoma Following Basal Cell Carcinoma

A spindle cell carcinoma arose three years after the seeming excision of a so-called "infiltrative" basal cell carcinoma (IBCC) in the cheek of an 87-year-old Japanese woman. The patent had no history of irradiation. The tumor was composed of short fascicles and whorling arrangements of spindle to polygonal cells without residual IBCC. Immunohistochemically, the tumor was positive for vimentin, cytokeratin 8 & 18, epithelial membrane antigen, and alpha-smooth muscle actin. Ultrastructurally, the tumor cells had tonofilaments and desmosomes. The patient died after a local recurrence with metastatic lesions in the lung and the neck lymph nodes that were indicated by CT scanning and MRI at nine months after diagnosis. This case and others support the concept that spindle cell carcinoma can pursue an aggressive clinical course.

Clinicopathologic variants of cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinomas (SCC) are one of the most common malignancies, which, with early recognition, may be curable. These tumors represent a broad spectrum of disorders with many significant clinical, morphologic, and etiologic distinctions. The objective of this article is to review the important clinicopathologic features of SCC with particular emphasis on important recent developments, practical application, and their relevance to the practice of pathology. The most pertinent literature of the last 5 years was reviewed and capsulized. Appropriate histologic interpretation and clinical management of patients with cutaneous SCC requires a comprehensive understanding of the latest advances in the broad field of dermatopathology. Squamous cell carcinoma of the skin represents a complex group of disease subtypes, each with its own characteristics, which may influence morphologic diagnosis as well as treatment and clinical management.

Spindle cell thymic carcinoma: clinicopathologic and immunohistochemical study of a distinctive variant of primary thymic epithelial neoplasm

We report 16 cases of a distinctive variant of primary thymic epithelial neoplasm characterized by prominent spindling of the tumor cells. The patients were seven women and nine men aged 23 to 82 years (mean, 54 years). The lesions presented as anterior mediastinal masses without clinical or radiographic evidence of tumor elsewhere. Most patients had chest pain, dyspnea, and cough; in five patients, the tumors were asymptomatic and were discovered on routine clinical examination. Grossly, the lesions were firm, well-circumscribed, and locally infiltrative, and had a firm cut surface with foci of hemorrhage, necrosis, and cystic changes. Most of the tumors were treated by complete surgical excision. Histologically, they were characterized by a spindle cell proliferation showing varying degrees of atypia and mitotic activity. In 12 cases, transitions could be seen with areas that showed the features of conventional spindle cell thymoma. In two cases, areas showing features of poorly differentiated (lymphoepitheliomalike) carcinoma and anaplastic carcinoma could also be observed. Immunohistochemical studies in 10 cases showed strong positivity of the spindle tumor cells for CAM5.2 cytokeratin, and negative staining for a panel of antibodies including epithelial membrane antigen, carcinoembryonic antigen, actin, desmin, vimentin, S-100 protein, HMB45, CD34, CD5, and CD99. Clinical follow-up of eight patients showed an aggressive biologic behavior with recurrence, metastasis, and death by tumor in five of them 2 to 5 years after diagnosis. Based on these findings, the present tumors are interpreted as an unusual spindle cell variant of thymic carcinoma. The close association of these cases with areas showing the features of spindle cell thymoma within the same tumor mass suggests that some of these lesions may arise as a result of malignant transformation in a preexisting spindle cell thymoma.

Diagnosis: atypical fibroxanthoma or not? Evaluating spindle cell malignancies on sun damaged skin: a practical approach

Poorly differentiated spindle cell malignancies on sun damaged skin frequently pose a diagnostic challenge for dermatopathologists. The vast majority of these neoplasms ultimately are diagnosed as either atypical fibroxanthoma (AFX), spindle cell squamous cell carcinoma (SCSCC), or spindle cell melanoma (SCM), and rarely leiomyosarcoma or angiosarcoma. Light microscopic clues may suggest one of these neoplasms, but subtle and overlapping characteristics often render precise diagnosis impossible based on morphological features alone. Immunohistochemistry therefore is necessary to firmly and accurately diagnose the majority of spindle cell malignancies on sun damaged skin. We summarize typical clinical and histological findings associated with this group of malignancies and offer a practical immunohistochemical approach to use in their diagnosis.

Spindle cell carcinoma of the gingiva: report of an autopsy case

An autopsied case of an 80-year-old man with spindle cell carcinoma of the gingiva is reported. The tumor was polypoid and mostly composed of a sarcomatous proliferation of spindle cells with a small focus of squamous cell carcinoma at the stalk portion. The carcinoma metastasized to a cervical lymph node, lungs and pleura with extension to the diaphragm. In the metastatic lymph node, the squamous cell component was more prominent than the spindle cell one, while only anaplastic pleomorphic carcinoma cells were found in the lungs. The spindle or anaplastic cells were immunohistochemically positive for vimentin and carcinoembryonic antigen (CEA) but not for other epithelial antigens. We have concluded that the sarcomatoid component arose from the oral squamous cell carcinoma by a metaplastic process. This is the first case report of an oral spindle cell carcinoma examined by autopsy.

A case of pseudovascular adenoid squamous cell carcinoma of the skin with spindle cell pattern

We report a case of pseudovascular adenoid squamous cell carcinoma which was in the form of a dome-shaped, cherry red tumor on the right cheek of an 86-year-old Japanese woman. Histologically, two types of atypical cells were identified; round cells in the upper part and spindle cells in the lower part. In the upper part, inter-anastomosing sinusoid-like pseudolumina were observed between the cords of the tumor cells. Immunohistochemically, the tumor cells did not express Factor VIII-related and CD34 antigens or bind Ulex europaes I agglutinin, except for only one anti-cytokeratin antibody. Ultrastructurally, the tumor cells contained tonofilaments and desmosomes and represented acantholysis. From the electron microscopy, possible role of capillary hyperpermeability on the acantholytic process of the neoplastic cells was suggested.

Primary metaplastic carcinoma (carcinosarcoma) of the skin. A clinicopathologic study of four cases and review of the literature

Metaplastic carcinoma (carcinosarcoma, sarcomatoid carcinoma, malignant mixed tumor) is a biphasic tumor comprising malignant epithelial and heterologous mesenchymal elements. Primary cutaneous cases are rare, with only seven cases documented in the English literature to date. We present four further cases, including three that developed in association with squamous cell carcinoma and one in an eccrine porocarcinoma. Heterologous malignant mesenchymal elements included malignant osteosarcoma, chondrosarcoma, leiomyosarcoma, and rhabdomyosarcomas. In contrast to metaplastic carcinomas arising in visceral sites, those primarily arising in the skin do not appear to behave in a very aggressive manner (Recurrence rate 22%, metastasis rate 22%, overall mortality 11%). However, the numbers involved are small and the follow-up period is short. In view of recent developments and progress in our understanding of the possible histogenesis of such tumors, we suggest that metaplastic carcinoma rather than carcinosarcoma is the most appropriate term with which to describe these very rare cutaneous neoplasms.

Atypical fibroxanthoma with osteoclast-like multinucleated giant cells

Atypical fibroxanthoma is a malignant fibrohistiocytic neoplasm that develops most commonly on sun-exposed skin of elderly individuals. A number of different variants have been described, ranging from a purely spindle cell type to a xanthomatous form. We recently observed an unusual variant of atypical fibroxanthoma in which there were numerous osteoclast-like multinucleated giant cells. Histologically, there was a diffuse spindle cell neoplasm in the dermis exhibiting fibrohistiocytic differentiation associated with inflammatory cells. The neoplastic spindle cells were markedly pleomorphic and many were in mitosis, some being tripolar and tetrapolar. In addition to these features, which are common in atypical fibroxanthoma, there were numerous multinucleated giant cells scattered throughout the lesion with features resembling normal osteoclasts. Epithelioid cells with features of histiocytes were seen in association with these cells. No osteoid was observed, however, that suggested monocyte-macrophage differentiation. The histologic appearance of this lesion was reminiscent of the giant cell variant of malignant fibrous histiocytoma, also termed malignant giant cell tumor of soft parts. Thus, osteoclast-like giant cells may be seen in atypical fibroxanthoma. These cells probably represent multinucleated histiocytes rather than true osteoclasts. It is important to recognize this variant to avoid confusion with other malignant soft tissue neoplasms.