Basaloid Epithelium Research Articles

DENTINOGENIC GHOST CELL TUMOR WITH FOCAL FEATURES SUGGESTING GHOST CELL ODONTOGENIC CARCINOMA: A CHALLENGING DIAGNOSIS

Dentinogenic ghost cell tumor and ghost cell odontogenic carcinoma form a spectrum of rare benign and malignant odontogenic neoplasms, respectively. A 24-year-old White woman complained of a painful enlargement and dental mobility in the maxilla for approximately 1 year. An intraoral examination showed a 3 × 3 cm firm exophytic mass in the left molar region. Tomographic sections showed a well-defined hypodense expansion with hyperdense foci inside invading the maxillary sinus. Microscopically, incisional sections showed a predominantly solid basaloid epithelium presenting atypical features, mitotic activity, ghost cells, positivity for p53, and high Ki-67 labeling, suggesting malignancy. Partial maxillectomy was performed. Surprisingly, the surgical specimen presented an important variation of the epithelial pattern and lacked any sign of malignancy, with abundant ghost cells and dentinoid, confirming the diagnosis of dentinogenic ghost cell tumor. A strict regular follow-up was done with no signs of recurrence or metastasis over 2 years.

Hedgehog Pathway Alterations Downstream of Patched-1 Are Common in Infundibulocystic Basal Cell Carcinoma

The infundibulocystic variant of basal cell carcinoma (BCC) is characterized histologically by anastamosing strands of basaloid epithelium with associated small infundibular-type cysts. Since its first description in 1987, this rare entity has generated considerable controversy with some authors classifying it as a benign follicular neoplasm rather than a BCC subtype. Prior studies aiming to settle this issue using immunohistochemical analysis reached opposite conclusions. The defining feature of BCC is activation of the Hedgehog signaling pathway, and mutations in Patched-1 (PTCH1) are the most common molecular finding in both sporadic and inherited forms of BCC. Mutations in other downstream components including Smoothened (SMO) and Suppressor of Fused (SUFU) also occur, but are much less common. Here, we report a molecular genetic analysis of a small series of infundibulocystic BCC using a next-generation DNA sequencing platform. All 4 cases harbored mutations or other genetic alterations in components of the Hedgehog pathway, supporting the classification of this entity as a BCC variant. Interestingly, these tumors were enriched for genetic alterations downstream of PTCH1, involving SUFU, SMO, GLI1, and GLI2. This observation was of particular interest given that rare kindreds of the Multiple Hereditary Infundibulocystic BCC syndrome (MHIBCC), which is related, but possibly distinct from the nevoid BCC syndrome, harbored mutations in SUFU. Our results support the classification of the infundibulocystic variant as a subtype of BCC, and suggest that the level at which genetic alterations occur within the Hedgehog pathway may be an important determinant of the morphologic features in BCC.

Fine-Needle Aspiration Cytology of Cellular Basaloid Neoplasms of the Salivary Gland.

Cellular basaloid neoplasms of the salivary gland represent a diverse group of benign and malignant neoplasms with significant cytomorphologic overlap on fine-needle aspiration cytology. All are marked by the presence of monotonous and usually bland basaloid epithelium. Distinction between basaloid neoplasms on fine-needle aspiration cytology is based on the presence or absence of additional features, including a second cell population (eg, myoepithelial cells), an acellular stromal component, and/or cytologic atypia within the basaloid epithelium. This review highlights the cytomorphologic features of the most common cellular basaloid neoplasms of the salivary gland, with an emphasis on classification and subclassification within the Milan System. To provide a comprehensive review of the cytologic features of basaloid epithelial neoplasms of the salivary gland, with an emphasis on classification within the Milan System for Reporting Salivary Gland Cytopathology. Peer-reviewed literature, recent textbooks, and personal experiences of the author. Some basaloid neoplasms, in particular pleomorphic adenomas and adenoid cystic carcinomas, may have characteristic findings on fine-needle aspiration that allow for definitive diagnosis. In other cases, however, fine-needle aspiration can confirm a neoplastic basaloid process, but specific classification of a benign or malignant neoplasm cannot be rendered. The Milan System for Reporting Salivary Gland Cytopathology acknowledges this difficulty, and recommends benign or malignant classification only when definitive diagnostic features of a specific neoplasm are present. For indeterminate cases, the subcategorization of salivary neoplasm of uncertain malignant potential is recommended.

ADENOMATOID ODONTOGENIC TUMOR, THE REPORT OF THREE CASES

Adenomatoid odontogenic tumor (AOT) is a rare benign odontogenic tumor. AOT represents 3-7% of all odontogenic tumors. First described by Steensland in 1905 and later by Philipsen and Bin in 1969, AOT is an encapsulated tumor composed by odontogenic epithelium with duct-like structures. Radiographically, it commonly appears as a pericoronal unilocular radiolucency associated with an impacted tooth, more often the maxillary canine. Frequently, the lesion shows focal calcifications. Most cases are discovered in the second decade of life. Some authors have considered AOT as a hamartoma rather than a neoplastic process. A peripheral variant has been described. Here, we report three cases of AOT to illustrated the benign course of this tumor. Cases The three cases were found in females at the age of 15, 18 and 33 years. One case was discovered the mandible as periapical lesion and two cases associated with impacted maxillary canines. All cases show well-defined mixed radiolucent and radiopaque appearance. Root resorption was not observed in the mandibular case. Slow growing was reported in all cases. An excisional biopsy was done in the three cases. Microscopically, all cases revealed an encapsulated tumor compose of sheets of solid basaloid epithelium with duct-like spaces. Cystic and solid patterns with dystrophic calcification were also observed. No recurrence has been reported. Conclusion Although, the mandibular case was located in an uncommon location and showed an atypical appearance, all cases demonstrated an indolent behavior. These cases confirm the benign nature of this tumor.

Intraoral Basal Cell Carcinoma, a Rare Neoplasm: Report of Three New Cases with Literature Review

Intraoral basal cell carcinoma (IOBCC) is an extremely rare entity that bears close microscopic resemblance to and is often confused with the peripheral ameloblastoma (PA). Basal cell carcinomas are thought to arise from pluripotential basal cells present within surface epithelium and adnexal structures, so theoretically they can arise within the oral cavity. Many of the early cases reported as IOBCC actually represent PA. Most of the well documented cases arise from the gingiva. The histologic features of basal cell carcinoma that help separate it from a PA include: tumor arising from surface epithelium, scattered mitotic figures and apoptotic cells, presence of mucoid ground substance and tumor infiltrating widely throughout the connective tissue and often exhibiting a prominent retraction artifact. Clinically IOBCC resemble carcinomas, compared to the benign and innocuous appearance of the PA and typically presents as surface ulcerations varying from rodent ulcer to an ulcerated erythroplakia appearance. This contrasts with the classic "bump on the gum" appearance of PAs with usually intact surface and appearing as small discrete, sessile, exophytic lesions. Importantly, the proliferative basaloid epithelium demonstrates positive immunoreactivity for the anti-epithelial antibody, Ber-EP4, a cell surface glycoprotein. The IOBCC has the potential for local recurrence and aggressive behavior and should be treated with wide surgical excision and close clinical follow up. We present 3 rare cases of IOBCC and discuss the salient histologic, immunohistochemical and clinical features.

Proliferating pilomatricoma with no recurrence during a 3-year follow-up

Proliferating pilomatricoma is a proliferative variant of pilomatricoma. Although it is considered as a benign tumor, local recurrence may occur. We report a case of a 49-year-old Japanese man with 3-year history of an asymptomatic subcutaneous tumor in the nuchal area. Histological evaluation demonstrated a cystic lesion lined by a basaloid epithelium at the periphery and filled with eosinophilic cornified material containing shadow cells in upper part of the tumor, and multilobular proliferation of basaloid cells in association with small foci of shadow cells in the remaining part. Based on these findings, the diagnosis of proliferating pilomatricoma was made. No recurrence has been observed during a 3-year follow-up.

Desmoplastic trichoepithelioma with perineural involvement: a series of seven cases

Desmoplastic trichoepithelioma (DTE) is a benign follicular tumor occurring most commonly within facial skin of young and middle-aged women, morphologically characterized by a superficial dermal proliferation of basaloid cells growing in narrow strands embedded in a desmoplastic stroma associated with small keratinizing cysts. DTE must be distinguished from other benign epithelial proliferations such as syringoma, microcystic adnexal carcinoma and infiltrating basal cell carcinoma. Among morphological features useful in that distinction, perineural involvement is considered a feature indicative of malignancy. We present a series of seven DTEs with otherwise typical presentation and morphology, nevertheless showing epithelium present in the perineural spaces of adjacent small dermal nerves. Patients ranged in age from 14 to 66 years (mean 44 years). All seven tumors were restricted to dermis, showed strands of basaloid epithelium in desmoplastic stroma and contained CK20-positive cells. Additionally, five of five examined tumors displayed diffuse expression of p75 neurotrophin receptor. Five patients were followed up clinically (follow-up time range: 2 months-4 years). No tumor recurrence was observed in any of these patients. We postulate that perineural involvement is an unusual feature of DTE that should not be equated with malignancy or lead to unnecessary over-treatment.

Basaloid squamous cell carcinoma with ‘monster’ cells: a mimic of pleomorphic basal cell carcinoma

Pleomorphic giant or 'monster' cells represent a well-recognized yet uncommon finding associated with basal cell carcinoma (BCC), usually of nodular type. We present a case of basaloid squamous cell carcinoma (basaloid SCC) with 'monster' cells that closely mimicked those described in pleomorphic nodular BCC. Clinically, the lesion presented as a fleshy, hyperkeratotic nodule in an 82-year-old woman. Histopathology revealed a basaloid lesion with lobulated borders and focal retraction artifact but a lack of prominent palisading or stromal mucin. There were areas of necrosis and small foci of keratinization. Striking bizarre monstrous pleomorphic nuclei were widely scattered throughout the lesion. Ber-EP4 immunohistochemistry proved to be negative and epithelial membrane antigen (EMA) expression was moderate to strong in 70% of the basaloid epithelium. Monster cells have not previously been highlighted in cutaneous SCC or in its uncommon cutaneous basaloid variant. The prognostic significance of monster cells is unknown but, given the relative paucity of keratinization in basaloid SCC, these lesions should probably be regarded as poorly differentiated. We have not previously encountered an SCC that so closely resembles nodular BCC with pleomorphic monster cells and believe that this is the first such report in the literature.

O31 Photodynamic therapy (PDT) of basocellular skin carcinoma

Basal cell carcinoma (BCC) is the prototypical basaloid tumour of the skin, but may show various patterns simulating other cutaneous tumours, particularly squamous cell carcinoma and trichoepithelioma (TE). Other challenges are presented by BCC with marked pleomorphism, glandular differentiation, neuroendocrine differentiation, clear cells and sarcomatoid change. Peripheral palisading and retraction (artefact) of the epithelium from the stroma are the most useful features to support a diagnosis of BCC, but can occasionally be seen in other benign and malignant cutaneous neoplasms and are inconspicuous or lacking in some cases of BCC. Increased ‘stromal’ mucin accompanying retraction and peripheral palisading is extremely suggestive of BCC and is rarely seen in other tumour types. Diffuse and strong BerEP4 staining and absence of epithelial membrane antigen staining is characteristic of BCC, and is an immunophenotype rarely encountered in other tumours except for TE. CD10 staining of the basaloid epithelium, in the absence of significant stromal staining, may support a diagnosis of TE-like BCC rather than TE in more organized variants.

Trichoblastoma of the Breast Detected by Screening Mammography: A Diagnostic Pitfall

Trichoblastoma of the Breast Detected by Screening Mammography: A Diagnostic Pitfall

Basaloid skin tumours: Basal cell carcinoma

Basal cell carcinoma (BCC) is the prototypical basaloid tumour of the skin, but may show various patterns simulating other cutaneous tumours, particularly squamous cell carcinoma and trichoepithelioma (TE). Other challenges are presented by BCC with marked pleomorphism, glandular differentiation, neuroendocrine differentiation, clear cells and sarcomatoid change. Peripheral palisading and retraction (artefact) of the epithelium from the stroma are the most useful features to support a diagnosis of BCC, but can occasionally be seen in other benign and malignant cutaneous neoplasms and are inconspicuous or lacking in some cases of BCC. Increased ‘stromal’ mucin accompanying retraction and peripheral palisading is extremely suggestive of BCC and is rarely seen in other tumour types. Diffuse and strong BerEP4 staining and absence of epithelial membrane antigen staining is characteristic of BCC, and is an immunophenotype rarely encountered in other tumours except for TE. CD10 staining of the basaloid epithelium, in the absence of significant stromal staining, may support a diagnosis of TE-like BCC rather than TE in more organized variants.

Congenital panfollicular nevus associated with polydactyly

A 2-year-old girl presented with ulnar-sided duplication of the left thumb distal to the interphalangeal joint and syndactyly of the first web space. She also had several asymptomatic pink-tan cutaneous papules, involving the first and second ray of the left hand and wrist, clinically resembling a linear epidermal nevus. Microscopically, the papules were composed of well-circumscribed aggregates of basaloid epithelium within the dermis. No normal hair follicles were identified. Follicular germ and papillae were identified, representing abortive attempts at hair follicle formation. The features were remarkably similar to a novel entity described by Finn and Argenyi as congenital panfollicular nevus. In our case, the congenital panfollicular nevus was associated with distal thumb polysyndactyly, which may suggest an important link between limb patterning and hair follicle development.

Congenital Panfollicular Nevus Associated with Polydactyly: a Second Case Report

A 2 year‐old girl presented with ulnar duplication of the left thumb distal to the interphalangeal joint and syndactyly of the first web space. She also had several asymptomatic pink‐tan cutaneous nodules involving the first and second ray of the left hand and wrist, clinically resembling a linear epidermal nevus. The patient underwent reconstruction of the duplicated left thumb, release of the syndactyly, and excision of the left wrist and hand skin lesions. Microscopically, the cutaneous nodules consisted of numerous well‐circumscribed aggregates of basaloid epithelium regularly distributed beneath the epidermis. No normal hair follicles were identified. There was evidence of incomplete hair follicle differentiation, with follicular germ and papillae, and there was a distinct fibrous sheath around the abortive follicular structures. The features were remarkably similar to a novel entity described by Finn and Argenyi in 2005 as congenital panfollicular nevus. In our case, the congenital panfollicular nevus was associated with polysyndactyly, which may provide evidence to support an important link between limb patterning and skin development. In summary, we describe an unusual congenital nevus comprised of many stages of hair follicle differentiation, and associated with a defect in limb patterning in this child.

Fibroepithelioma of Pinkus Presenting as a Sessile Thigh Nodule

A 68‐year‐old white man noticed the rapid enlargement of a newly appearing, painless lesion on his left leg during the previous month. There was no history of arsenic ingestion or local radiotherapy. A nontender, lobulated, sessile, red, 15×15×10 mm nodule protruded from the lateral side of his proximal right thigh (Figure 1). A tangential excision of the lesion was performed and the surgical site was allowed to heal by secondary intention. Microscopic examination showed anastomosing strands of basaloid cells extending from the overlying epidermis into the dermis (Figure 2). Some of the basaloid cells had atypical nuclei. Eccrine ducts were present within the strands of tumor cells. A fibromucinous stroma loosely surrounded the tumor. Focally, in the deeper portions of the tumor within the reticular dermis there was palisading of the peripheral row of cells and retraction of these tumor cells from the surrounding stroma (Figure 3). The tumor was completely removed in the sections examined. The pathologic changes were characteristic for the diagnosis of fibroepithelioma of Pinkus variant of basal cell carcinoma. Distant (A) and closer (B) views of a fibroepithelioma of Pinkus that presents on the patient's lateral right proximal thigh as a sessile nodule image Crusted polypoid nodule with a proliferation of anastomosing strands of basaloid epithelium embeded in abundant dense fibrous tissue (hematoxylin‐eosin stain, original magnification×4)image Another view shows some areas with stromal edema and focal retraction from the reticulated basaloid tumor (hematoxylin‐eosin stain, original magnification×4).image

Morphological stages of pilomatricoma.

In 1983, Ackerman proposed that pilomatricoma represents an infundibular-matrix cyst in its early stages. To study the evolution of this cystic neoplasm, we examined 118 lesions from 116 patients with pilomatricoma histopathologically and categorized the lesions into four distinct and chronological stages: early, fully developed, early regressive, and late regressive. Early lesions (eight cases) were small cystic structures lined by squamoid and basaloid epithelium containing keratin filaments and faulty hair matrix material composed of shadow cells. Fully developed lesions (27 cases) were large neoplasms lined by basaloid epithelium at their periphery, and within, composed of irregularly shaped, densely packed zones of cornified masses containing shadow cells. Early regressive lesions (37 cases) had no apparent epithelial lining but did have basaloid cell foci at the periphery; within, they were composed of pink hair matrix material with shadow cells surrounded by granulation tissue with inflammatory infiltrate and multinucleated histiocytic giant cells. Late regressive lesions (42 cases) had no epithelial component and were composed of irregularly shaped, partially confluent masses of faulty hair material, and calcified (and sometimes metaplastically ossified) shadow cells embedded in a desmoplastic stroma, with little or no inflammatory infiltrate. In four cases, there was a relatively large dermal nodule composed of several interconnected lobules that consisted largely of basaloid cells with only a few areas of shadow cells. We interpreted these lesions as proliferating pilomatricomas. Based upon our histopathologic findings, we propose that pilomatricomas may be categorized into four distinct morphological stages and that these stages reflect the "life" of a pilomatricoma. Thus, the lesion begins as an infundibular matrix cyst and ends up as a calcified and ossified nodule with no visible epithelial component.

Keratinocyte transglutaminase in human skin and oral mucosa: cytoplasmic localization and uncoupling of differentiation markers

Expression of keratinocyte transglutaminase, a specific differentiation marker, has been examined by immunogold-silver cytochemistry in human epidermis and oral epithelium, and in oral mucosal hyperplasia and neoplasia. Two major findings have been obtained. First, considerable immunoreactivity was evident not only at the plasma membrane (the site of cross-linked envelope formation) but also in the cytoplasm of spinous cells, suggesting a cytoplasmic function for this transglutaminase. Staining at the cell border was seen principally in the granular layer of orthokeratinized epithelium (epidermis, hard palate), the outer spinous cells of ortho- and parakeratinized epithelium and in the suprabasal cells showing squamous differentiation in benign and malignant neoplasms. By contrast, diffuse cytoplasmic staining was observed in the upper spinous layer of the normal epithelium and benign lesions. The cytoplasmic immunoreactivity, which extended nearly to the basal layer in hyperkeratosis of the oral mucosa, was evident in two of three verrucous carcinomas examined. In keeping with their undifferentiated character, invasive nests of squamous cell carcinoma and basaloid epithelium in benign and neoplastic lesions were immunonegative for transglutaminase. The second major finding was that lesions of severe oral epithelial dysplasia, immunonegative for transglutaminase, were capable of expressing involucrin immunoreactivity, indicating an uncoupling of keratinocyte programming. These results suggest that immunogold-silver staining for transglutaminase may be useful in evaluating the degree of differentiation in benign and malignant oral epithelial proliferation.

Involucrin Expression in Normal and Neoplastic Human Skin: A Marker for Keratinocyte Differentiation

Involucrin is a recently recognized structural component of mature squamous epithelial cells. We examined involucrin expression using an immunoperoxidase technique in normal skin and in a variety of epidermal hyperplasias and neoplasms to determine whether distinctive staining patterns existed within these lesions. Four patterns of reactivity were observed: diffuse intracellular staining typical of keratinocytes of the upper third of normal epidermis and epidermal hyperplasias and benign neoplasms; staining at cell borders, seen principally in benign epidermal neoplasms; patchy staining characteristic of squamous cell carcinoma in situ; and absence of staining in benign and neoplastic basaloid epithelium. Invasive nests of squamous cell carcinomas were negative for involucrin reactivity, whereas pseudoinvasive tongues of epithelium at the bases of keratoacanthomas were focally positive. These results suggest that immunoperoxidase staining for involucrin may be useful in distinguishing certain benign from malignant epidermal neoplasms as well as in understanding the altered maturation and kinetics of proliferative processes afflicting keratinocytes.