Clear cell squamous cell carcinoma. A histologic, immunohistologic, and ultrastructural study

Clear Cell Proliferations of the Skin: A Histopathologic Review

ABSTRACT

Cutaneous clear cell proliferations encompass a heterogenous group of several primary cutaneous neoplasms and metastatic tumors with different histogenesis. Many of these clear cell proliferations may seem strikingly similar under the microscope resulting in challenging diagnosis. In many of these clear cell lesions, the reason for the clear or pale appearance of proliferating cells is unknown, whereas in other ones, this clear cell appearance is due to intracytoplasmic accumulation of glycogen, mucin, or lipid. Artifacts of tissue processing and degenerative phenomenon may also be responsible for the clear cell appearance of proliferating cells. Awareness of the histopathologic findings as well as histochemical and immunohistochemical techniques are crucial to the accurate diagnosis. This review details the histopathologic features of clear cell cutaneous proliferations, classifying them according their type of differentiation and paying special attention to the histopathologic differential diagnosis among them.

Cutaneous Squamous Cell Carcinoma: Review of the Eighth Edition of the American Joint Committee on Cancer Staging Guidelines, Prognostic Factors, and Histopathologic Variants

Cutaneous squamous cell carcinoma is the second most common form of nonmelanoma skin cancer after basal cell carcinoma and accounts for the majority of nonmelanoma skin cancer-related deaths. In 2017, the American Joint Committee on Cancer revised the staging guidelines of cutaneous squamous cell carcinoma to reflect recent evidence concerning high-risk clinicopathologic features. This update reviews the literature on prognostic features and staging, including the eighth edition of the American Joint Committee on Cancer Staging Manual. A wide range of histopathologic variants of cutaneous squamous cell carcinoma exists, several of which are associated with aggressive behavior. A review of cutaneous squamous cell carcinoma variants, emphasizing diagnostic pitfalls, immuhistochemical findings and prognostic significance, is included. Of note, the eighth edition of the American Joint Committee on Cancer Staging Manual refers to squamous cell carcinoma of the head and neck only.

Lobulated Bowen's Disease with a Clear Cell Change

Bowen's disease usually manifests as a slowly enlarging erythematous scaly patch or plaque. An uncommon variant of Bowen's disease showing a verrucous appearance has been reported and a distinct variant with a prominent clear cell change on histopathology, in addition to a verrucous surface change, was also reported. We describe novel form of Bowen's disease having a cerebriform appearance and showing histopathologically a significant clear cell change and propose that the clinical term "lobulated Bowen's disease" would be compatible for the description of this unique clinical variant. From a histopathological point of view, the precise definition and etiopathogenesis of the clear cell change in Bowen's disease should be elucidated.

Malignant Clear Cell Acanthoma: Report of a Rare Case of Clear Cell Acanthoma-Like Tumor With Malignant Features

An erythematous and moist tumor nodule on the left temple of a 92-year-old woman was biopsied and identified as a clear cell acanthoma (CCA)-like tumor with malignant cytology and high proliferation activity. This case is similar to 2 cases reported previously as atypical CCA. The authors believe that these tumors are malignant counterparts of CCA and propose to call them malignant CCA. The clinicopathologic features of the present case are described along with dermoscopic findings.

Clear cell variant of squamous cell carcinoma originating in the esophagus: report of a case with immunohistochemical and oncogenetic analyses

The cutaneous clear cell squamous cell carcinoma (SCC) is a rare tumor thought to be associated with hair follicle or skin appendage differentiation. We report herein a rare variant case of a clear cell SCC originating in the esophagus. A 70-year-old Japanese man was found to have a tumor in the esophagus. The excised neoplasm showed dominance of clear cell over conventional SCC components; the two components in an apparent continuum. The clear cells, regular in size with a moderate nuclear/cytoplasmic ratio and relatively hyperchromatic and centrally located nuclei, were compactly arranged in sheets. Glycogen deposition was apparent on PAS staining with or without diastase digestion and under the electron microscope. The clear cell SCC components were positive for cytokeratin (CK)7, CK8, CK18 and CK19, but were negative for CK5/6 or CK14. Reciprocal staining patterns of CKs were apparent in conventional SCC components. The present case and cutaneous clear cell SCC counterparts share some histopathologic characteristics whereas CKs expression differs between the two. Overexpression of p53 protein, without evidence of any mutation, and reduced p16(INK4a) were noted in both clear cell and conventional SCC components. No mutations of Kras, BRAF or β-catenin genes were found in both tumor components.

Primary squamous cell carcinoma of fallopian tube accompanied by gastric metaplasia of female genital tract: case report and review

Primary squamous cell carcinoma arising from the fallopian tube (SCCFT) is extremely rare with only six reported cases. We report a case of primary SCCFT accompanied by multifocal pyloric glandular metaplasia in the genital tract. An accompanying review of the literature describes the characteristics of this rare histological subtype invading into the muscular layer of the fallopian tube to involve adjacent pelvic organs, while the most common serous type tends to spread into the abdominal cavity through tubal ducts. Due to the low response rate of adjuvant therapies, the 5-year survival rate of patients bearing primary SCCFT at stage II-IV is very poor, only accounting for 25%. All patients were alive without disease where optimal resection had been successfully achieved. These findings imply that radical tumor resection is mandatory for satisfactory treatment of primary SCCFT.

Pitfalls and procedures in the histopathological diagnosis of oral and oropharyngeal squamous cell carcinoma and a review of the role of pathology in prognosis

Histopathological assessment of formalin-fixed biopsy tissue and surgical resection specimens remains the cornerstone of cancer diagnosis and pathological staging in routine clinical practice. In recent years, standard protocols for reporting head and neck cancer have been widely used and these have improved the general level of the pathological assessment. In this article, we look beyond the standard protocols and deal with potential difficulties and pitfalls in the assessment of incisional biopsy specimens, surgical resection specimens and neck dissections. We draw attention to possible shortcomings and issues requiring clarification. Emphasis is given to precise histopathological definitions, histopathological detection and differential diagnosis. The approach is a practical one--a consideration of common experiences and dilemmas faced by the reporting pathologist, and where possible, we offer guidance and practical tips. The article concludes with a brief consideration of the prognostic value of accurate histopathological staging.

Adnexal clear cell carcinoma with comedonecrosis: clinicopathologic analysis of 12 cases

CONTEXT

Cutaneous clear cell tumors can pose a diagnostic challenge even to the experienced dermatopathologist; this is partly because of limitations of existing diagnostic categories.

OBJECTIVE

To describe a previously unrecognized, distinctive cutaneous adnexal carcinoma capable of an aggressive clinical course.

DESIGN

Clinicopathologic analysis of a series of 12 cases.

RESULTS

The patients were older individuals (median age, 71 years) with equal gender frequency. The lesions showed wide anatomic distribution with predilection for the head and neck area, especially the scalp. The lesions presented as rapidly growing, erythematous to flesh-colored, solitary papules/nodules that were capable of quickly reaching a size of several centimeters. Histologically, adnexal clear cell carcinoma with comedonecrosis was characterized by dermal proliferation of nests of epithelial cells showing distinctive zonal arrangement. The periphery of the tumor nests was formed by squamoid cells merging with centrally located clear cell areas containing foci of comedonecrosis. The lesions often showed multilobular or trabecular growth pattern and infiltrating border. Nuclear pleomorphism was variable; mitotic count ranged from 2 to 32/mm2 (median, 8/mm2). No ductal, cuticular, or apocrine differentiation was seen. All cases showed expression of epithelial membrane antigen and cytokeratin 17 in clear cells, with focal carcinoembryonic antigen expression in some cases. Follow-up (average, 37 months) revealed local recurrence (4 cases) and regional and distant metastases (2 cases).

CONCLUSIONS

Adnexal clear cell carcinoma with comedonecrosis appears to be a distinctive adnexal neoplasm that has to be distinguished from more indolent squamous cell and tricholemmal carcinomas.

Coincidental Consort Clear Cell Cutaneous Carcinoma: Facial Squamous Cell Carcinoma In Situ Containing Human Papillomavirus and Cancer Cells with Clear Cytoplasm in an Octogenarian Couple

Clear cell squamous cell carcinoma in situ, also referred to as pagetoid or clear cell Bowen disease, is a rare pathologic variant of this neoplasm. It is characterized by neoplastic cells with clear or pale cytoplasm. An octogenarian husband and wife concurrently developed new facial skin lesions which demonstrated squamous cell carcinoma in situ consisting of cancer cells with clear cytoplasm. Cutaneous human papillomavirus (HPV) typing detected HPV Type 5 and HPV Type 21 in the tumors of the husband and wife, respectively. HPV is a potential etiologic factor in the oncogenesis of nonmelanoma skin cancer, and HPV DNA has been demonstrated in extragenital squamous cell carcinoma in situ. The detection of DNA from different HPV types in the tumors of our patients suggests that the concurrent occurrence of their skin cancers may have been coincidental. However, the presence of HPV DNA in their tumors introduces the possibility of a viral-associated oncogenesis for clear cell squamous cell carcinoma in situ.

Highly Aggressive Extraocular Sebaceous Carcinoma

Extraocular sebaceous carcinoma is an uncommon neoplasm usually localized on the head and neck. We report a case of sebaceous carcinoma of the axillary skin with a highly aggressive behavior. The patient was a 43-year-old black man who developed multiple cutaneous and lymph node metastases shortly after the excision of primary sebaceous carcinoma of the axillary skin. Many neoplastic aggregations were identified within the lumina of the dermal lymphatic vessels in the excised specimen of the primary neoplasm. Although extraocular sebaceous carcinoma has been traditionally considered a less aggressive neoplasm than its ocular counterpart, a review of the literature and this case demonstrate that extraocular sebaceous carcinoma may also lead to disseminated metastatic disease.

Signet-ring squamous cell carcinoma: a case report

A-50-year-old Hispanic man presented to the dermatology clinic with a 0.6-cm eroded, erythematous, scaly plaque on the left side of his neck. On shave biopsy, the lesion was composed of intra-epidermal and invasive dermal cells characterized by a signet-ring appearance. One area suggestive of typical squamous cell carcinoma prompted the inclusion of that entity in the differential diagnosis. Mucicarmine stains were negative, while the extra-vacuolar cytoplasm focally reacted with periodic acid-Schiff staining, the positive reaction for which was abolished by diastase, consistent with glycogen. Malignant cells expressed keratins by reacting to antibodies, Mak6, AE1/AE3, Ker 903, and CAM5.2. Additionally, weak reactivity occurred with antibodies to CEA and EMA. Tumor cells did not express S-100, HM-B45, Leu M1, or actin. By ultrastructural examination, the large vacuoles corresponded to markedly dilated endoplasmic reticulum. A diagnosis of signet-ring squamous cell carcinoma, a rare form of cutaneous squamous cell carcinoma which has been described in only one case report in the last 10 years, was made. Immunohistochemical staining provided information useful in differentiating this lesion from other clear cell and signet-ring cell tumors which involve the skin.

Clear cell basal cell carcinoma: an unusual degenerative variant

Clear cell basal cell carcinoma (BCC) is an unusual variant of BCC which is characterized by a variable component of large clear cells. Twenty cases are presented which are further subdivided into pure, mixed, or metatypical categories. Although initially thought to represent sebaceous or tricholemmal differentiation, electron microscopic studies demonstrated that the clear cell changes are a degenerative phenomenon, probably involving lysosomes.