Atypical Basal Cell Research Articles

A case of basal cell carcinoma of skin with bone metastasis: a case report

BackgroundBasal cell carcinoma is the most prevalent skin cancer, most characterized by local aggressiveness but with low metastatic potential, and bone metastasis is quite heterogeneous, thus the incidence profile is variable size from 0.0028% to 0.5%. We have this patient with an unusual example of basal cell carcinoma with bone metastases to add to the scarce report on this matter.Case descriptionHere we document a 48-year-old Persian man with a background of being exposed to the sun for a long time. He was diagnosed with an ulcer on the cheek, which was clinically characterized and further confirmed by biopsy as morpheaform basal cell carcinoma. Following the first round of excision, multiple relapses eventually metastasized to the bone. The latter was found on follow-up radiologic scans. This case is characterized by the aggressive nature of the disease and the heterogeneity of basal cell carcinoma growth, thus challenging the conventional view of basal cell carcinoma behavior. Treatment included surgical excision of the primary lesion, which was treated with radiotherapy afterward. However, the skeleton improved slowly during follow-up, and palliative care was eventually pursued to control symptoms and improve quality of life.ConclusionsThis was a rare case of basal cell carcinoma metastasis to non-bone organs, which reminded us to consider basal cell carcinoma metastasis, especially in the case of atypical basal cell carcinoma. Therefore, risk-aware patient management is essential. Moreover, these findings highlight the role of further research into the mechanisms of basal cell carcinoma metastasis, leading to improved therapeutic strategies that may lead to potential improvements in patient outcomes.

Хирургическое лечение базалиомы внутреннего угла глазной щели с закрытием дефекта свободным лоскутом. Клинический случай

Basal cell carcinoma is a tumor of the basal layer of the skin epithelium. It occupies an intermediate position between benign and malignant tumors. It develops from atypical basal cells of the epidermis and follicular epithelium. It does not metastasize. The occurrence on the lower eyelid is about 65 %, on the medial canthus about 15 %, on the upper eyelid about 15 % and on the lateral canthus 5 % of cases. Usually the neoplasm is painless, but more invasive basal cell carcinomas with perineural germination into the tissues of the eyelid and orbit can cause pain [1, 3]. The choice method of treatment of this disease is surgical. The operation is performed under a microscope, which allows to remove the altered tissues as much as possible and correctly match the edges of the donor material. To replace the surgical defect, a type of plastic was chosen: plastic with local tissues, free skin plastic. The skin flap was taken from the upper eyelid of the fellow eye [2]. There are several types of basal cell carcinomas: nodular, flat, and superficial. The nodular form is most common. A distinctive feature in most cases is pearl shade and waxy or translucent consistency of the tumor, more noticeable on the raised edges of the neoplasm. A characteristic and important symptom is telangiectasis marked at the edges of the neoplasm [1]. Initially, a painless nodule appears on the skin gradually, the nodule spreads over the area, accompanied by formation of ulcers, due to disturbance of blood supply and turns into ulcerative-nodular form. Ulceration can bleed. Further, basal cell carcinoma turns into a flat plaque with a peeling surface, a node protruding above the surface of the skin, or into a deep ulcer that destroys the underlying tissues. With advanced forms or inadequate treatment, the tumor can grow into the lacrimal pathways, the orbit and occasionally into the cranial cavity. The sprouting of orbital tumor causes diplopia and dislocation of the eyeball. Spontaneous regression is rare [3]. There are the following types of treatment: radiation, surgical, combined, medicinal, cryogenic, laser [4, 5]. Radiation, laser, cryogenic methods of treatment are carried out in a specialized cancer center. The surgical method is based on excision within healthy tissues with the least traumatization or destruction of surrounding tissues. Excision of a part of the eyelid weakens its horizontal tension; this circumstance requires special restorative techniques to prevent scarring. The choice method of the defect closure is the method of lateral displacement, plastic with a free flap or pedicle flap [4, 5]. Key words: basal cell carcinoma; surgery of basal cell carcinoma; plastic surgery with a free flap.

The detectability of intraepidermal melanocytes-A narrative review of immunohistochemical studies.

Some intraepidermal lesions, even the nonmelanocytic ones, may mimic melanoma in situ. The cytoplasmic clarity in atypical basal cells, architectural disorder with cell aggregates or nest-like structures within the epidermis often cause challenge particularly in sun-damaged skin. The aim of this review is to evaluate the effectiveness of the most often used immunohistochemical melanocyte markers in the diagnosis of intraepidermal lesions. All the analyzed markers can be useful in detection of intraepidermal melanocytes that occur more densely in lentigo maligna than in solar lentigo or sun-damaged skin. However, the number of these cells is underestimated by HMB-45 and Mel-5. The cytoplasmic Melan-A staining may overestimate melanocyte number and highlight the dendritic process. Atypical melanized keratinocytes in actinic keratoses and nest-like structures in lichenoid dermatoses may mimic atypical melanocytes in melanomas in situ. S-100 remains a marker of high sensitivity but low specificity. The nuclear localization of MITF, SOX-10, and PRAME overcomes the problem of melanosome transfer to cells of other types. Neither MITF nor SOX-10 is detectable in keratinocytes, which makes them useful in distinguishing actinic keratoses from melanomas in situ. The use of markers considered as melanocyte specific suggests that lichenoid dermatoses constitute a heterogeneous group of lesions.

Reflectance confocal microscopy findings in a case of molluscum contagiosum

We present the case of a 74-year-old man who presented for his annual skin check and had a new suspicious lesion on his left cheek consistent with a pink-white papule showing a mixed vascular pattern (Fig 1). The patient had a medical history of 2 previously treated basal cell carcinomas on his face. The lesion was clinically suspicious for a new-onset basal cell carcinoma. The patient was referred for reflectance confocal microscopy to confirm the nature of the lesion. Nonpolarized contact dermatoscopy revealed a pink and yellow to white, relatively well-demarcated papule with a central clod-like, very faintly polylobular, white-to-yellow, amorphous structure (Fig 2). This central area corresponded to the round-to-oval lobules seen on confocal microscopy and to the central lobulated endophytic hyperplasia seen on histopathology (Fig 3).Fig 3Molluscum contagiosum - reflectance confocal microscopy, zoomed in. Higher magnification into the central lobular area revealed hyper-refractive cell outlines with hyporefractive central areas within these lobules. Note the slightly grainy cytoplasm of these cells, corresponding to Henderson-Paterson(molluscum) bodies. It was necessary to alter the brightness and contrast in the reporting software (Vivanet) to better visualize the individual cell outlines (Vivascope 1500, Caliber I.D.; Imaging & Diagnostics, Inc).View Large Image Figure ViewerDownload Hi-res image Download (PPT) The vascular pattern was mixed, with a few focal crown-like vessels and multiple prominent circumferentially arranged radial blood vessels, some exhibiting a branching pattern. Shiny white structures were not readily appreciated. The dermatoscopic differentials by a panel of experts at consensus included a possible sebaceous neoplasm given the polylobular appearance and focal crown vessels or a basal cell carcinoma with atypical dermatoscopic features given the radial blood vessels with some arborizing features. Confocal microscopy (Vivascope 1500, Caliber I.D.; Imaging & Diagnostics, Inc) revealed a well-circumscribed lesion with central, relatively uniform, hyporefractive, round-to-oval lobules forming a central polylobular structure (Fig 4). This central polylobular area corresponded to the central yellow-to-white clod seen on dermatoscopy. Higher power confocal microscopy views of the individual lobules revealed multiple slightly hyperrefractive cells within each lobule. The individual cells with large, round, hyperreflective intracytoplasmic inclusions corresponded to the Henderson-Paterson bodies observed on histology. Because of the fact that the authors were unfamiliar with the confocal findings, biopsy was performed to rule out possible sebaceous neoplasm or an atypical basal cell carcinoma. The hyporefractive lobules in the central section of the lesion exhibited the typical histopathology of molluscum contagiosum (MC) with a central area displaying lobules and endophytic hyperplasia (Fig 5). At the microscopic single-cell level, hyper-refractive round-to-oval cells within each lobule observed at reflectance confocal microscopy corresponded histologically to the individual enlarged keratinocytes containing intracytoplasmic eosinophilic, hyalinized viral inclusions that displaced the nucleus peripherally (Henderson-Paterson bodies), a typical finding of MC. MC usually has a typical clinical and dermatoscopic appearance on which most diagnoses are based. Some lesions, however, may have an unusual morphology, making clinical or dermatoscopic evaluation challenging or equivocal. This may sometimes lead to suspicion for neoplasm, necessitating biopsy and histopathologic evaluation. In this case, an evaluation of the findings and currently available literature appears to suggest that the reflectance confocal microscopy findings of MC are very characteristic and reproducible, even when MC lesions appear atypical clinically or on dermatoscopy.1Broggi G. Verzì A.E. Micali G. Caltabiano R. Lacarrubba F. Horizontal histopathology correlates with in vivo reflectance confocal microscopy features of molluscum contagiosum: a case series.J Cutan Pathol. 2021; 48: 1430-1431https://doi.org/10.1111/cup.14106Crossref PubMed Scopus (2) Google Scholar,2Cinotti E. Perrot J.L. Labeille B. Cambazard F. Reflectance confocal microscopy for cutaneous infections and infestations.J Eur Acad Dermatol Venereol. 2016; 30: 754-763https://doi.org/10.1111/jdv.13254Crossref PubMed Scopus (38) Google Scholar Awareness of the confocal findings of MC among new confocal microscopists could avoid unnecessary biopsies for these benign lesions. None disclosed.

Unusual dermoscopic patterns of basal cell carcinoma mimicking melanoma.

BackgroundBasal cell carcinoma can simulate melanoma and specific dermoscopic criteria have not yet been defined in a large cohort.ObjectiveTo identify dermoscopic “trump” characteristics for differential diagnosis, identify cluster groups and assess the clinical impact of this study's findings.MethodsRetrospective, multicentric comparative study of atypical, non‐facial basal cell carcinoma (≥1 seven‐point checklist criteria) and melanoma (with at least one BCC criteria) at dermoscopy. Observed dermoscopic features were used to develop a proposed score. Lesion clusters were defined with hierarchical analysis. Clinical impact was assessed with a blinded reader study following this study's results.ResultsA total of 146 basal cell carcinoma and 76 melanoma were included. Atypical vascular pattern was common to most lesions (74.5%). Twelve trump features were included in the proposed score (sensitivity 94.1% and specificity 79.5%). Cluster analysis identified 3 basal cell carcinoma and 3 melanoma clusters. Findings improved overall diagnostic accuracy and confidence (26.8% and 13.8%, respectively; p < 0.001).ConclusionsThese findings support the notion that atypical vascular pattern should be considered a shared feature of both melanoma and atypical basal cell carcinoma. Our proposed score improves diagnostic accuracy and confidence. Absence of pigmented features was associated with lower diagnostic accuracy and confidence.

Vulvar intraepithelial neoplasia. Literature review

Vulvar intraepithelial neoplasia (VIN) is the proliferation of atypical basal cells in the vulvar epithelium. The global VIN incidence has recently doubled; its incidence among white women under 35 years of age has almost tripled with a tendency for further growth. Such an increase in the number of usual-type VIN cases in young women is primarily attributed to infection with highly oncogenic human papillomavirus. The second type of dysplasia, namely differentiated VIN, is usually found in older women and is associated with chronic dystrophic diseases of the vulva, most frequently with lichen sclerosus of the vulva. VIN diagnosis is quite challenging; no screening programs for this disorder have been developed so far. Patients with VIN practice self-treatment for a long time, which aggravates their condition and might trigger the development of vulvar cancer. Several treatment options are currently available; however, their efficacy worldwide is not high.

Lesions Mimicking Melanoma at Dermoscopy Confirmed Basal Cell Carcinoma: Evaluation with Reflectance Confocal Microscopy

Background: Atypical basal cell carcinoma (BCC), characterized by equivocal dermoscopic features typical of malignant melanoma (MM), can be difficult to diagnose. Reflectance confocal microscopy (RCM) enables in vivo imaging at nearly histological resolution. Objectives: To evaluate with RCM atypical melanocytic lesions identified in dermoscopy, according to common RCM criteria for the differential diagnosis of BCC, and to identify representative RCM parameters for superficial (sBCCs) and nonsuperficial (nsBCCs) basal cell carcinomas (BCCs). Methods: A retrospective analysis of consecutive patients evaluated with RCM, selecting excised lesions classified at dermoscopy with ≥1 score from the re visited 7-point checklist, mimicking melanoma, registered between 2010 and 2016. Cluster analysis identified BCC subclassifications. Results: Of 178 atypical lesions, 34 lesions were diagnosed as BCCs with RCM. Lesions were confirmed BCCs with histopathology. Dermoscopic features included atypical network (55.9%) and regression structures (35.5%) associated with sBCCs, and an atypical vascular pattern (58.8%) and irregular blotches (58.8%) with nsBCCs. Hierarchical cluster analysis identified 2 clusters: cluster 1 (100% sBCCs) was characterized by the presence of cords connected to the epidermis (90%, p < 0.001), tumor islands located in the epidermis (100%, p < 0.001), smaller vascular diameter (100%, p < 0.001) and solar elastosis (90%, p = 0.017), and cluster 2 (nsBCCs 85%) was defined by the dermic location of tumor islands (87.5%, p < 0.001) with branch-like structures (70.8%, p = 0.007) and surrounding collagen (83.3%, p = 0.012), peripheral palisading (83.3%, p = 0.012) and coiled vascular morphology (79.2%, p < 0.001) with a larger vascular diameter (50%, p < 0.001). Conclusions: RCM is able to diagnose BCCs mimicking melanoma at dermoscopy and seems able to identify sBCCs and nsBCCs.

Actinic keratosis with atypical basal cells (AK I) is the most common lesion associated with invasive squamous cell carcinoma of the skin.

Progression from actinic keratosis (AK) to invasive squamous cell carcinoma (iSCC) of the skin is thought to occur after the development of full thickness epidermal neoplasia, as in the classic pathway of cervical cancer. Nevertheless, cutaneous iSCC may also directly arise from a proliferation of atypical basaloid cells limited mostly to the epidermal basal layer (AK I), akin to what happens in the 'differentiated pathway' of iSCC of the vulva, oral cavity and other locations. To evaluate the prevalence of classic and differentiated pathways in the development of cutaneous iSCC. The epidermis adjacent to and overlying iSCC, assumed to be representative of pre-existing lesions, was histologically studied in 196 skin biopsy specimens showing iSCC. AK I, AK II and AK III lesions overlying iSCC were present in 63.8%, 17.9% and 18.4% of cases respectively. The corresponding percentages in the epidermis adjacent to iSCC were 77.9%, 6.6% and 8.3% respectively (stage could not be assessed in 8.1% of cases). Focal epidermal ulceration overlying iSCC was seen in 32% of AK I, 28.6% of AK II and 33.3% of AK III instances. Adnexal involvement by atypical keratinocytes (proliferative AK) was present more frequently in cases with overlying AK I (39/125, 31.2%) than with AK II (8/35, 22.9%) and AKII I (5/36, 13.9%). Direct invasion from proliferating basaloid atypical keratinocytes limited to the epidermal basal layer (AK I), known as the differentiated pathway, was the most common form of progression to cutaneous iSCC in our series. On the other hand, stepwise progression from AK I to AK II and AK III (classic pathway) was seen to be operative in a substantial proportion of iSCC cases. All AK lesions, irrespective of intraepidermal neoplasia thickness, are therefore potentially invasive and tumour advance along adnexal structures might facilitate iSCC development from AK I lesions.

Prostate Cancer With Aberrant Diffuse p63 Expression: Report of a Case and Review of the Literature and Morphologic Mimics

We report a case of a prostatic adenocarcinoma that showed diffuse aberrant p63 expression in the secretory cells and review the literature and differential diagnosis. p63-positive prostatic adenocarcinoma is rare and is typically encountered when working up an atypical focus with basal markers and α-methylacyl coenzyme A racemase. These carcinomas have unusual morphologic features such as atrophic cytoplasm and basaloid morphology. The differential diagnosis includes basal cell hyperplasia and basal cell carcinoma; morphologic features such as the presence of small, infiltrative acini with nuclear atypia, lack of high-molecular-weight cytokeratin expression, and positive α-methylacyl coenzyme A racemase and prostate-specific antigen expression can help distinguish a p63-positive prostatic adenocarcinoma from atypical basal cell proliferations. Current controversies regarding the grading, prognosis, and molecular profile of p63-positive prostatic adenocarcinomas are also discussed.

Focal neuroendocrine differentiation in prostatic gland carcinoma with basaloid pattern

Prostatic gland basal cell proliferations exhibit morphological continuum ranging from basal cell hyperplasia to basal cell carcinoma. In the following report, we described clinical features, morphological spectrum, neuroendocrine differentiation and histogenesis of prostatic gland basal cell carcinoma in our patient. Hematoxylin-eosin (HE), Alcian blu-periodic acid schiff (AB-PAS) at pH 2.5 stained sections and the avidin-biotin-peroxidase complex (ABC), were performed on prostate gland paraffin-embedded tissue. Monoclonal antibodies directed against cytokeratin (34betaE12) which selectively stains basal cells, prostate specific antigen (PSA), chromogranine A, neuron-specific enolase (NSE), synaptophysin and CD56, were used. Basal cell proliferations exhibited a morphological continuum ranging from basal cell hyperplasia to prostatic gland carcinoma. In these prostatic lesions, positive reactivity was demonstrated for 34betaE12 and CD56. These findings indicate that the basaloid cells of basal cell hyperplasia, florid basal cell hyperplasia, atypical basal cell hyperplasia and basal cell carcinoma are derived from basal cells of the normal prostate gland suggesting a continuum in the progression of hyperplasia to benign and then malignant neoplasia. The presence of CD56 protein in the discovered lesions may be related to their neuroendocrine differentiation. The fact, that our patient was well six years after the radical prostatectomy supports the belief of some authors that basal cell carcinoma represents a low grade carcinoma with an excellent prognosis.

Big Bad BCCs: Craniofacial resection and reconstruction for atypical basal cell carcinomata

Basal cell carcinoma (BCC) is the most common malignancy of the body and most frequently occurs in the head and neck. 'Problematic aggressive' BCCs are either frequently recurrent, often after histologically confirmed clearance, or are 'giant/horrifying' and invasive of critical anatomy. Three patients that illustrate different clinical features and outcomes of 'problematic aggressive' craniofacial BCCs are reported that required craniofacial resection and reconstruction with microsurgical free flap cover, and a re-evaluation of our care pathway for these uncommon presentations.

Essential Role for Pbx1 in Corneal Morphogenesis

The Pbx TALE (three-amino-acid loop extension) homeodomain proteins interact with class 1 Hox proteins, which are master regulators of cell fate decisions. This study was performed to elucidate the role of the Pbx1 TALE protein in the corneal epithelium of mice. Pbx1(f/f) mice were crossed with mice containing Cre recombinase under the control of the K14 promoter. Subsequently, the eyes of these mice were dissected and prepared for histologic or molecular analysis. Tissue-specific deletion of Pbx1 in the corneal epithelium of mice resulted in corneal dystrophy and clouding that was apparent in newborns and progressively worsened with age. Thickening of the cornea epithelium was accompanied by stromal infiltration with atypical basal cells, severe disorganization of stromal collagen matrix, and loss of corneal barrier function. High epithelial cell turnover was associated with perturbed expression of developmental regulators and aberrant differentiation, suggesting an important function for Pbx1 in determining corneal identity. These studies establish an essential role of the Pbx1 proto-oncogene in corneal morphogenesis.

Aberrant Diffuse Expression of p63 in Adenocarcinoma of the Prostate on Needle Biopsy and Radical Prostatectomy: Report of 21 Cases

Aberrant diffuse expression of p63 in prostate carcinoma cells is a rare and poorly understood phenomenon. We studied 19 cases of prostate cancer with aberrant diffuse expression of p63 on needle biopsy and reviewed the subsequent radical prostatectomies in 6 cases. In 19/21 cases, 100% of the cancer nuclei stained intensely for p63, with 70% staining in the remaining 2 cases. Two additional radical prostatectomies with aberrant p63 staining with no needle biopsies available for review were also analyzed. On the hematoxylin and eosin-stained slides, 19/21 cases (90.5%) showed a distinctive morphology composed predominantly of glands, nests, and cords with atrophic cytoplasm, hyperchromatic nuclei, and visible nucleoli. Needle biopsy cases ranged from Gleason patterns 3 to 5 with tumor identified on one or more cores, ranging from a minute focus to 80% of the core. In all 8 radical prostatectomies p63 positive cancer was present, with in 2/8 cases both p63 positive cancer and usual p63 negative acinar prostate cancer. In all 8 cases, the tumors were organ confined with negative margins and there was no seminal vesicle involvement or lymph node metastasis. The presence of p63 positive atypical glands with an infiltrative pattern and perineural invasion on radical prostatectomy confirmed the needle biopsy diagnosis of carcinoma. Rarely, prostate cancer can aberrantly express diffuse p63 staining in a nonbasal cell distribution leading to the erroneous diagnosis of atrophy or atypical basal cell proliferation. The diagnosis of prostate cancer is based on the morphology and confirmed by the absence of high molecular weight cytokeratin staining and positivity for alpha-methylacyl-CoA racemase in the atypical glands. Pathologists need to be aware of this rare and unusual phenomenon, which is a potential pitfall in prostate cancer diagnosis.

Clinical applicability of in vivo fluorescence confocal microscopy for noninvasive diagnosis and therapeutic monitoring of nonmelanoma skin cancer

Excisional biopsies and routine histology remains the gold standard for the histomorphologic evaluation of normal and diseased skin. However, there is increasing interest in the development of noninvasive optical technologies for evaluation, diagnosis, and monitoring of skin disease in vivo. Fluorescent confocal microscopy is an innovative optical technology that has previously been used for morphologic evaluation of live human tissue. We evaluate the clinical applicability of a fluorescent confocal laser scanning microscope (FLSM) for a systematic evaluation of normal and diseased skin in vivo and in correlation with routine histology. A total of 40 patients were recruited to participate in the study. Skin sites of 10 participants with no prior history of skin disease served as controls and to evaluate topographic variations of normal skin in vivo. Thirty patients with a suspected diagnosis of nonmelanoma skin cancer were evaluated, whereby FLSM features of actinic keratoses (AK) and basal cell carcinoma (BCC) were recorded in an observational analysis. Selected BCCs were monitored for their skin response to topical therapy using Imiquimod as an immune-response modifier. A commercially available fluorescence microscope (OptiScan Ltd., Melbourne, Australia) was used to carry out all FLSM evaluations. Common FLSM features to AK and BCC included nuclear pleomorphism at the level of the granular and spinous layer and increased vascularity in the superficial dermal compartment. Even though the presence of superficial disruption and mere atypia of epidermal keratinocytes was more indicative of AK, the nesting of atypical basal cells, increased blood vessel tortuosity, and nuclear polarization were more typical for BCC. All diagnoses were confirmed by histology. FLSM allowed a monitoring of the local immune response following therapy with Imiquimod and demonstrated a continuous normalization of diseased skin on repeated evaluations over time. This study illustrates potential applications of FLSM in clinical dermatology for the evaluation of dynamic skin conditions and monitoring of cutaneous response to noninvasive therapies. The findings are of preliminary nature and warrant further investigations in the future.

Carcinosarcoma of monoclonal origin arising in a dermoid cyst of ovary: a case report

BackgroundTransformation of a cystic benign teratoma of the ovary into a "carcinosarcoma" has very rarely been reported and its histogenetic origin is still debated.Case presentationA case of carcinosarcoma arising from a dermoid cyst is reported. The tumor showed cystic areas delimited by normal squamous epithelium, with transitional areas through dysplastic epithelium to "in situ" and infiltrating squamous cell carcinoma (SCC).The sarcomatous component showed compact tissue composed of round cells concentrically arranged around small vessels, spindle, and pleomorphic cells with a high nuclear-cytoplasmic ratio.Positive staining for vimentin, alpha smooth muscle actin and CD10, as well as P53 and P63, was found in the sarcomatous component and in some atypical basal cells of the squamous epithelium, which also showed the usual epithelial markers.ConclusionTo the best of our knowledge, this is the first case of carcinosarcoma arising from a dermoid cyst in which a histogenetic origin from totipotent stem cells, located in the basal squamous layer, is supported by immunohistochemical findings.

Simultaneous tumour-like, atypical basal cell hyperplasia and acinar adenocarcinoma of the prostate: a comparative morphological and genetic approach

Basal cell tumours of the prostatic gland are rare, and the classification is difficult. In the present case report, a large, tumour-like proliferation of atypical basaloid cells was found incidentally in a prostatectomy specimen that otherwise contained a conventional acinar adenocarcinoma. The basaloid cells displayed a solid or adenoid-cystic growth pattern and strongly expressed high-molecular-weight cytokeratins and bcl-2. A high Ki-67 index was recorded within the atypical basaloid cells, by far exceeding the one counted in the conventional adenocarcinoma. However, there were no definite criteria for a malignant behaviour of the basal cell tumour. Comparative genomic hybridisation from microdissected tumour cells yielded losses at the short arms of chromosomes 8 and 12 in the conventional adenocarcinoma and a normal karyotype in the basal cell tumour. The pathological findings favoured the diagnosis of an atypical basal cell hyperplasia.

CD117, CK20, TTF-1, and DNA topoisomerase II-alpha antigen expression in small cell tumors.

Distinguishing merkel cell carcinoma (MCC), small cell lung carcinoma (SCLC) metastatic to the skin, and atypical basal cell carcinoma (BCC) can be problematic in some cases. Significant differences in the biology of these tumors necessitate that they need to be distinguished from one another. We evaluated the immunophenotypic characteristics of 22 MCCs, nine SCLCs, and 19 BCCs using antibodies to cytokeratin 20 (CK20), thyroid transcription factor-1 (TTF-1), CD117, and DNA topoisomerase II-alpha (topo II). Nineteen of 22 MCCs stained with the antibody to CK20, none stained with anti-TTF-1, and 13 stained with anti-CD117. No SCLC stained with anti-CK20, all stained with anti-TTF-1, and eight stained with anti-CD117. No BCC stained with any of the three markers. The proliferative index (PI), determined by the expression of topo II, was similar for SLCLs (mean 58.5 +/- 9.0%) and MCCs (mean 45.2 +/- 12.4%) and was lowest in BCCs (mean 25.0 +/- 8.7%). CK20 and TTF-1 appear to be reliable in distinguishing MCC from SCLC. CD117 is expressed in both MCC and SCLC, limiting its diagnostic utility. CK20, TTF-1, and CD117 are not expressed in BCC. The high PI seen in MCCs suggests a role for topoisomerase II inhibitors in their treatment.

Rapid diagnosis of clinically atypical basal cell carcinoma by cytomorphology

Rapid diagnosis of clinically atypical basal cell carcinoma by cytomorphology

Atypical Basal Cell Hyperplasia of the Prostate

Atypical Basal Cell Hyperplasia of the Prostate

Basal cells in human bronchial epithelium.

The morphology and distribution of basal cells were investigated in adult human bronchial epithelium. In both smokers and non-smokers typical basal cells were more numerous than atypical basal cells, which were distinguished by their spindle-shaped nucleus, polar cytoplasm, and processes that extended along the basal lamina. The nucleus of the atypical basal cell was consistently closer to the muco-ciliary surface than was the nucleus of the typical basal cell. In cross-sections of bronchi the numbers of typical basal cells/mm epithelium were greatest in large airways; in smaller bronchi (i.e., generations 7-16) the frequency declined. The numbers of atypical basal cells/mm epithelium were similar throughout the bronchial tree. Throughout the bronchial tree both types of basal cells contributed to the maintenance of epithelial cohesion by providing desmosomal attachment for columnar cells. The importance of typical basal cells in this role was indicated by their greater numbers, which collectively presented a large surface for epithelial cell attachment by desmosomes. The surface presented by the cell body and processes of each atypical basal cell for attachment of columnar cells by desmosomes was extensive. If the basal cell is the most important progenitor of bronchial epithelium and the cell at risk in the development of lung cancer, the presence of more basal cells in upper airways, where many lung cancers originate, may be significant. The basal cell populations in larger bronchi are perhaps the greatest concentration of cells with proliferative capability and potential for neoplastic transformation in the human bronchial tree.