Pigmented squamous cell carcinoma of the alveolar ridge in the oral mucosa

Uncommon Pigmented Carcinoma In Situ: Case Report and Brief Review

Pigmented lesions of the oral mucosa encompass several benign and malignant conditions that may be a matter of concern under both clinical and histopathological views. We reported a case of a 62-year-old woman, presenting with an asymptomatic, deeply pigmented lesion on the soft palate. On examination, it appeared asymmetrical, with irregular borders and an area of ulceration. A biopsy, taken to rule out melanoma, revealed a pigmented carcinoma in situ. Throughout the tumor thickness, numerous interspersed melanocytes were found that did not extend to neighboring epithelium. These were large, richly dendritic, and presented abundance of melanin granules and small nuclei. Mild melanin incontinence was found. Scanty transfer of pigment to dysplastic epithelial cells was found through Fontana Masson staining. On immunohistochemical analyses, there were pancytokeratin-stained tumor epithelial cells; increased cell proliferation throughout the entire thickness of the tumor was emphasized by Ki-67 immunomarking. P16 was negative. The dendritic cells were selectively stained for S-100, HMB45 and Melan A. Wide spectrum in situ hybridization for human papillomavirus (HPV) was negative. Unfortunately, following diagnosis, the patient refused any treatment option. Pigmented squamous cell carcinoma with melanocyte colonization must be taken into account in the differential diagnosis of pigmented lesions of the oral cavity.

Clinicopathological and immunohistochemical characteristics of pigmented oral squamous cell carcinoma

Pigmented oral squamous cell carcinoma (POSCC) is a rare and underrecognized pathological variant of oral squamous cell carcinoma (OSCC). The current study aimed to evaluate the clinicopathological characteristics, treatment outcomes and prognosis of patients with POSCC and to investigate its oncological properties using immunohistochemical studies. A total of 1,512 patients were pathologically diagnosed with squamous cell carcinoma of the oral cavity, and were treated at the Department of Oral and Maxillofacial Surgery, Tokyo Medical and Dental University between January 2001 and December 2018. A total of 25 patients had POSCC and underwent radical surgery. Of these 25 patients, 23 presented with early T stage disease. Additionally, 22 patients were negative for cervical lymph nodes metastasis. Only one patient had local recurrence. The 5-year disease-free and disease-specific survival rates were 86.6 and 95.8%, respectively. Immunohistochemically, a high percentage of POSCC exhibited low p53 and Ki-67, preserved E-cadherin or negative vimentin expression. The results suggested that POSCC tends to exhibit non-aggressive oncological behavior and demonstrates a good prognosis.

Pigmented Squamous Cell Carcinoma In Situ: Report of a New Case and Review of the Literature

Pigmented squamous cell carcinoma in situ (PSCCIS) is very rare, being clinically described as a pigmented lesion with histological characteristics of an in-situ carcinoma presenting pigmentation within neoplastic cells. A 50-year-old Afro-descendant man came for clinical evaluation of a painful black and red lesion located on the right aspect of the oropharyngeal isthmus. After incisional biopsy, the resulting sample was described as a pigmented squamous cell carcinoma in situ, a diagnosis further confirmed by immunohistochemical analysis. Treatment consisted in total excision of the lesion, and no recurrence was observed after a 30-month follow-up. Clinicians and pathologists should be aware of PSCCIS as a differential diagnosis of melanoma, a lesion which significantly increases the morbidity and mortality rates among these patients.

Key words:Pigmented squamous cell carcinoma in situ; oropharyngeal mucosa; immunohistochemistry.

Pigmented oral carcinoma in situ: a case report and literature review

Oral melanotic lesions, including melanin pigmentation, melanocytic nevus, and malignant melanoma, are well-recognized pathologic entities. However, melanocytic proliferation within malignant oral mucosal lesions is not well documented. We report the unusual case of a 53-year-old Japanese man who developed oral carcinoma in situ (CIS) with melanocytic proliferation and melanin pigmentation in the epithelial layer. The patient, a nonsmoker and an opportunistic drinker, presented with a brown tongue lesion. Initial examination found a large brown pigmented area and multiple small white patchy areas on the right tongue border. The pigmentation had an ill-defined border with uneven color distribution. Physical examination found no abnormalities. Ultrasonography did not find a deeply infiltrating lesion. Oral mucosal malignant melanoma in situ was diagnosed, and partial tongue resection was performed. Histopathologic examination found oral pigmented CIS. To the best of our knowledge, this is only the third reported case of oral pigmented CIS.

Pigmented squamous cell carcinoma in situ of the conjunctiva in 5 cases

PURPOSE

To describe 5 patients with pigmented conjunctival squamous cell carcinoma in situ.

DESIGN

Retrospective noncomparative case series.

PARTICIPANTS

Five patients.

METHODS

Clinical and histopathologic features were reviewed.

MAIN OUTCOME MEASURES

Relationship of clinical and histopathologic features to carcinoma pigmentation.

RESULTS

All 5 patients were male. Two were Hispanic, 2 were Caucasian, and 1 was Asian Indian. Localized racial melanosis was evident in 3 cases and no case showed diffuse racial melanosis. The tumor showed leukoplakia (n = 1) and was at the temporal limbus (n = 4) or nasal limbus (n = 1). The mean tumor basal dimension was 9.2 mm and mean thickness was 3.2 mm. Brown pigment was present deep within the tumor in all 5 cases, involving 50% to 90% of the mass. In each case, pigmented squamous cell carcinoma was suspected; melanoma was a second possibility. Histopathology revealed in situ squamous cell carcinoma (conjunctival intraepithelial neoplasia) with pigmented dendritic melanocytes in all 5 cases. Pigment was also found within neoplastic cells (n = 2). After surgical resection, there was no recurrence over mean follow-up of 23 months.

CONCLUSIONS

Squamous cell carcinoma in situ can manifest as a pigmented tumor, resembling melanoma, in both Caucasians and non-Caucasians, primarily due to intratumoral pigmented dendritic melanocytes.

Pigmented oral squamous cell carcinoma: a case report and brief review of the literature

Melanin impregnation in squamous cell carcinoma (SCC) is an uncommon histological finding. Rare nonmelanocytic entities were previously described as having melanocyte colonization. A 57-year-old Brazilian woman was referred with a pigmented lesion in the lower lip and alveolar ridge with a prior clinical diagnosis of melanoma. The incisional biopsy of the tumor revealed an SCC with strong colonization of melanocytes in the stroma. The authors report a case of an unusual SCC variant and a brief review of the literature.

Possible involvement of stem cell factor and endothelin-1 in the emergence of pigmented squamous cell carcinoma in oral mucosa

We present here the clinical, morphological and immunohistochemical features of a pigmented squamous cell carcinoma (SCC) in the oral mucosa of the hard palate of a 76-year-old Japanese man. He underwent a partial resection of the maxilla subsequent to radiotherapy. The tumor was typical, moderately well-differentiated SCC but had many melanocytes (melanocytosis) within it. Immunohistochemical analysis for stem cell factor (SCF) and endothelin-1, both of which are known to stimulate proliferation and differentiation of melanocytes, revealed prominent expression of both factors in the neoplastic squamous cells of the pigmented SCC, while the non-pigmented oral SCC showed little sign of either factor. These findings strongly suggest that SCF and endothelin-1 secreted by neoplasmic squamous cells are involved in the emergence of a rare variant of oral SCC.

Pigmented squamous cell carcinoma of the uterine cervix

A 57-year-old female presented with an abnormal Pap smear. Colposcopic examination of the cervix revealed white mucosa with erosion and several areas of black pigmentation. After a colposcopically directed biopsy and loop conization, radical hysterectomy and bilateral salpingo-oophorectomy with pelvic and paraaortic lymphadenectomy were performed. Pathological examination disclosed an invasive squamous cell carcinoma admixed with many dendritic melanocytes. Melanin granules were present within the melanocytes and tumor cells. Although similar tumors have been reported in other sites, this is the first report to our knowledge of a pigmented squamous cell carcinoma of the uterine cervix.

Pigmented squamous cell carcinoma of the cheek skin probably arising from solar keratosis

We report a rare case of pigmented squamous cell carcinoma (SCC) of the cheek skin probably arising from solar keratosis. An 80-year-old man was referred to our clinic because of a black skin nodule in the right cheek. The nodular lesion was 1 cm in diameter, dome-shaped, hard, sharply demarcated, partially erosive and telangiectatic at the border. The lesion was completely excised under the clinical diagnosis of probable seborrheic keratosis. Microscopically, cutaneous horn and mildly atypical squamous epithelia suggestive of previous solar keratosis were present in the surface of the lesion. The lesion consisted of atypical squamous cells with keratinization and intercellular bridges, and it was regarded as SCC. The SCC cells were seen to invade lightly into the upper dermis, where lymphocytic infiltrations and melanophages were noted. Characteristically, heavy deposition of melanin pigment was recognized in the SCC cells as well as in proliferated dendritic and pigment blockade melanocytes that were scattered or colonized within the SCC cell nests. Masson-Fontana stain revealed numerous melanin granules in the SCC cells, as well as in dendritic and pigment blockade melanocytes. Immunohistochemically, the SCC cells were positive for cytokeratins and epithelial membrane antigen, and negative for S-100 protein and HMB45 antigen. Dendritic and pigment blockade melanocytes were negative for cytokeratins, epithelial membrane antigen, and HMB45 antigen, but positive for S-100 protein. The present case suggests that SCC cells of the skin may induce proliferation of melanocytes. The differential diagnosis and the histogenesis of pigmented SCC of the skin are discussed.

Uterine carcinosarcoma with melanocytic differentiation

A 65-year-old black woman was found to have a 3.0 cm endometrial tumor that was a carcinosarcoma with a major epithelial and a less prominent mesenchymal component. The latter was undifferentiated but one focus of chondroid differentiation was noted. The former showed papillary serous differentiation. Melanin pigment was observed in both epithelial and mesenchymal components. Staining with antisera to S100 protein and HMB-45 confirmed the presence of melanocytes. An endocervical focus of tumor also contained melanin. Electron-microscopic studies showed large tumor cells with an irregularly indented nucleus and abnormal giant cytoplasmic melanosomes. Only one case of uterine carcinosarcoma with melanocytic differentiation has been previously reported.

Pigmented squamous cell carcinoma with dendritic melanocyte colonization in the external auditory canal

A case of pigmented squamous cell carcinoma (SCC) with dendritic melanocyte colonization in the external auditory canal is reported and the previous cases are reviewed. A 65-year-old Japanese female was referred with a 7-year history of otitis. The patient also had a darkly pigmented 9 x 8 mm nodule in the external auditory canal. Microscopically, the tumor was SCC, but in some areas melanin pigments were found in the cytoplasm of the tumor cells. The tumor was thus diagnosed as pigmented SCC. As well as the tumor cells, dendritic-shaped cells colonized the tumor parenchyma and were immunohistochemically defined as melanocytes. The authors believe this is the first case of pigmented SCC with dendritic melanocyte colonization in the external auditory canal.

Pigmented squamous cell carcinoma of the scrotum associated with a lentigo

Only 13 cases of pigmented squamous cell carcinoma (SCC) have been reported in the English language literature, with most frequent development in the oral cavity and conjunctiva. However, no case of pigmented SCC of the scrotum has been reported. We report here a case of pigmented SCC that arose primarily in the scrotum of a 70-year-old man. Light microscopically, this tumour exhibited the typical features of a pigmented SCC, including not only keratinization and intercellular bridges but also colonization by plump dendritic melanocytes with marked pigmentation. These features were clearly confirmed by immunohistochemistry, including strong positivity of tumour cells for high-molecular-weight cytokeratin and of colonizing melanocytes for HMB-45. The tumour was associated with a lentiginous lesion and partly involved it. Melanocytes entrapped from the lentigo might therefore have been activated during enlargement of this tumour, resulting in melanocyte colonization. Fourteen cases of pigmented SCC, including ours, are clinicopathologically reviewed.

Pigmented squamous cell carcinoma of the skin: report of two cases and review of the literature

Melanoma is the most common malignant tumor in which melanin synthesis occurs, although other nonmelanocytic tumors synthesize melanin or contain nonneoplastic melanocytes. We present two cases of infiltrating pigmented squamous cell carcinoma of the skin and review the clinical, morphologic, and ultrastructural features. Melanin was found in epithelial tumor cells as well as in macrophages and dendritic melanocytes. Interestingly, one of the neoplasms was associated with an adjacent melanocytic nevus and pigmented solar keratosis. Immunohistochemical analysis showed that neoplastic cells stained for keratin and melanin-filled dendritic cells were found to be S-100 protein and HMB45 positive. A careless examination of the immunohistochemical stains for S-100 protein and HMB45 could cause the misdiagnosis of melanoma, a neoplasm that has a more ominous outlook.

Pigmented squamous cell carcinoma with dendritic melanocytes

A 79-year-old man presented with a pigmented nodule on the right ear which, on epiluminescence microscopy, demonstrated a diffuse grey-blue colour. Skin biopsy revealed an irregularly acanthotic epidermis with lobular clusters of atypical keratinocytes that projected into the dermis in the pattern of an invasive squamous cell carcinoma. Numerous dendritic melanocytes were present throughout the lesion. Although the close relationship between the highly dendritic intra-epidermal melanocytes and the atypical keratinocytes raised the issue of whether this tumour represented a malignant melanoacanthoma, the authors considered the lesion to be better classified as an unusual variant of pigmented squamous cell carcinoma.