Pigmented Squamous Cell Carcinoma of Oral Mucosa: Clinicopathologic Study of 3 Cases

J Oral Maxillofac Surg 70:1232-1239, 2012

Pigmented Squamous Cell Carcinoma of Oral Mucosa: Clinicopathologic Study of 3 Cases Toshinari Mikami, DDS, PhD,* Izuru Furuya, DDS, PhD,† Akiko Kumagai, DDS, PhD,‡ Hideyuki Furuuchi, DDS, PhD,§ Hideki Hoshi, DDS, PhD,储 Shin Iijima, DDS,¶ Yoshiki Sugiyama, DDS, PhD,# and Yasunori Takeda, DDS, PhD** Squamous cell carcinoma (SCC) of the skin and mucosa occasionally show pleomorphic histologic forms. One of these rare pleomorphic forms is pigmented SCC (PSCC). Although melanin pigments are widely distributed in the skin and in certain types of mucosa, PSCC is

*Assistant Professor, Division of Oral Pathology, Department of Pathogenesis and Control of Oral Diseases, Iwate Medical University School of Dentistry, Iwate, Japan. †Clinical Fellow, Division of Oral Surgery, Department of Oral and Maxillofacial Surgery, Iwate Medical University School of Dentistry, Iwate, Japan. ‡Assistant Professor, Division of Oral Surgery, Department of Oral and Maxillofacial Surgery, Iwate Medical University School of Dentistry, Iwate, Japan. §Assistant Professor, Division of Oral Surgery, Department of Oral and Maxillofacial Surgery, Iwate Medical University School of Dentistry, Iwate, Japan. 储Associate Professor, Division of Oral Surgery, Department of Oral and Maxillofacial Surgery, Iwate Medical University School of Dentistry, Iwate, Japan. ¶Assistant Professor, Division of Oral Surgery, Department of Oral and Maxillofacial Surgery, Iwate Medical University School of Dentistry, Iwate, Japan. #Professor, Division of Oral Surgery, Department of Oral and Maxillofacial Surgery, Iwate Medical University School of Dentistry, Iwate, Japan. **Professor, Division of Oral Pathology, Department of Pathogenesis and Control of Oral Diseases, Iwate Medical University School of Dentistry, Iwate, Japan. This study was supported, in part, by Grants-in-Aid for the Open Research Project (2007-2011) and Grant-in-Aid for Strategic Medical Science Research Center (2010-2014) from the Ministry of Education, Culture, Sports, Science and Technology of Japan. Address correspondence and reprint requests to Dr Mikami: Division of Oral Pathology, Department of Pathogenesis and Control of Oral Diseases, Iwate Medical University School of Dentistry, 19-1 Uchimaru Morioka, Iwate 020-8505, Japan; e-mail: toshi_m@sea .plala.or.jp © 2012 American Association of Oral and Maxillofacial Surgeons

0278-2391/12/7005-0$36.00/0 doi:10.1016/j.joms.2011.03.048

rarely seen.1-22 Only 12 cases of PSCC in the oral mucosa have been reported.1,2,15,17,19,20,22 Clinically, the differential diagnosis of PSCC with dark pigmentation often includes melanoma and other melanocyte lesions. However, PSCC is not always accompanied by dark pigmented lesions on the overlying epithelium,19,20 although many melanin pigments and melanocytes can be found intermingled with the tumor cells. Although only 1 case of metastasis has been reported,13 and no tumor recurrence has been reported in each follow-up term, the potential malignancy of PSCC in oral mucosa is still unknown. The present report describes the clinical and histopathologic features of PSCC.

Case Reports CASE 1 In June 2007, a 40-year-old Japanese man with a history of tobacco use (20 cigarettes daily) and alcohol use was referred to our university hospital with a chief complaint of an erosion of the tongue. An intraoral examination revealed a painless erosion 12 mm in diameter, with an induration in the left lateral region of the tongue (Fig 1A). Clinically, pigmentation associated with the area of erosion was observed, and gallium scintigraphy showed abnormal accumulation in the tongue region. The patient was clinically diagnosed with carcinoma of the tongue. The TNM classification was T1N0M0, and the tumor was surgically excised. The 33-month follow-up examination after surgical treatment showed no evidence of local recurrence or metastasis. CASE 2 In February 2007, a 49-year-old Japanese woman with a history of tobacco use (15 pieces daily) and alcohol use was referred to our university hospital with a chief complaint of a swelling on the mouth floor. She had a 5- to 6-year history of a slowly enlarging painless swelling and, a few years previously, had noted a dark pigmentation. The patient had a history of hepatitis C. An intraoral examination revealed an erosion near the salivary gland opening on the mouth floor. In the anterior region of the mouth floor, there was a 3 ⫻ 2-mm dark patch that was centered on a 10 ⫻ 8 mm erythematous lesion with an unclear boundary (Fig 1B). From a clinical perspective, the swelling was not clear, and the induration was not palpable. The computed tomography, gallium scintigra-

1232

1233

MIKAMI ET AL

tion after surgical treatment showed no evidence of local recurrence or metastasis. CASE 3

FIGURE 1. Photographs of clinical presentation. A, Case 1. Clinically, erosion seen in left lateral region of tongue, but no pigmentation seen. B, Case 2. Erythematous lesion and 3 ⫻ 2-mm dark patch seen on mouth floor. C, Case 3. Anterior papillomatous tumor measuring 45 ⫻ 23 mm on left buccal mucosa and more posterior irregular pigmented mass with 12mm-long process. Mikami et al. Pigmented Squamous Cell Carcinoma of Oral Mucosa. J Oral Maxillofac Surg 2012.

phy, and bone scintigraphy results were normal, and no obvious tumor lesion was found on the mouth floor. The clinical diagnosis revealed the condition to be pigmentation of the oral mucosa. The histopathologic results from a biopsy of the lesion led to a diagnosis of PSCC. The tumor was surgically excised, and radical neck dissection was also performed. The 39-month follow-up examina-

In November 2007, a 78-year-old Japanese woman with no history of tobacco or alcohol use was referred to our university hospital with a chief complaint of swelling on the buccal mucosa. The patient had a history of uterine myoma. The tumor consisted of an anterior, painless, papillary-like component measuring 45 ⫻ 23 mm on the left buccal mucosa and a more posterior, irregular pigmented mass with a 12-mm-long process. Between these 2 tumor lesions, leukoplastic changes were not seen, and the boundary of the posterior lesion was unclear. Dark pigmentation was observed in the tumor and surrounding normal epithelium (Fig 1C). Although a dark pigmentation with erythema was also seen on the hard plate, it appeared to be independent of the buccal lesion. A panoramic radiograph did not show any destructive bony changes. Metastasis of the tumor and swelling of the lymph nodes were not detected by ultrasonography, computed tomography, or magnetic resonance imaging performed before surgery. The patient was clinically diagnosed with tumor of the buccal mucosa. The biopsy specimens showed a papillomatosis lesion with cellular atypia. Surgical resection with the patient under general anesthesia was performed in January 2008, and the tumor was excised with a 5-mm safety margin. The histopathologic diagnosis was PSCC. Postoperatively, from the results of both gallium scintigraphy and bone scintigraphy, metastasis was not suspected. In July 2008, 6 months postoperatively, at a periodic medical examination, recurrence of the SCC near the maxillary tubercle was suspected. Biopsy specimens from the patient showed a papillomatosis lesion with cellular atypia. The pathologic diagnosis was verrucous hyperplasia. In November 2008, another biopsy from the patient showed a papillomatosis lesion with cellular atypia, which was similar in appearance to the first biopsy taken in November 2007. SCC recurrence was strongly suspected; however, we did not see an invasion of tumor cells. Magnetic resonance imaging showed a tumor-like mass in the region between the maxillary tubercle and the left upper canine, and we also suspected that the cancer had metastasized to the lymph node because of finding an enlarged lymph node (Fig 2A-C). In January 2009, the patient underwent chemotherapy, consisting of 2 cycles of Taxotere, cisplatin, and 5-fluorouracil given 2 weeks apart. Radiotherapy was administrated to the primary lesion (52 Gy) and to the neck (40 Gy). After treatment, the size of the primary lesion and metastatic lymph nodes was smaller than in November 2008. At 20 months of follow-up after chemotherapy and radiotherapy, no signs of local recurrence or metastasis were seen. SPECIAL STAINING AND IMMUNOHISTOCHEMISTRY The surgically removed tissues were fixed in 20% neutral-buffered formalin and embedded in paraffin. Sections 4-␮m thick of the representative tissues were prepared for staining. Immunohistochemical studies were performed to determine the tumor components using the ChemMate EnVision Detection Kit/HRP (DAB) Rabbit/Mouse (Dako, Glostrup, Denmark), HMB-45 monoclonal 1:100 (Dako), S-100 protein polyclonal 1:100 (Immunotech, Marseilles, France), Melan A monoclonal 1:50

1234

PIGMENTED SQUAMOUS CELL CARCINOMA OF ORAL MUCOSA

FIGURE 2. Case 3. Magnetic resonance imaging findings at 10 months postoperatively. Tumor recurrence strongly suspected (circles). A, T1-weighted magnetic resonance image showing recurrence of primary tumor. B, Proton-weighted magnetic resonance image. (Figure 2 continued on next page.) Mikami et al. Pigmented Squamous Cell Carcinoma of Oral Mucosa. J Oral Maxillofac Surg 2012.

1235

MIKAMI ET AL

FIGURE 2 (cont’d). C, T2-weighted magnetic resonance image showing suspected metastasis of tumor to lymph nodes. Mikami et al. Pigmented Squamous Cell Carcinoma of Oral Mucosa. J Oral Maxillofac Surg 2012.

(Dako), high-molecular-weight keratin monoclonal 1:50 (Dako), and low-molecular-weight keratin monoclonal (Becton Dickinson, Franklin Lakes, NJ). The sections for Melan A and HMB-45 were pretreated with 0.25% potassium permanganate or hydrogen peroxide to bleach the melanin.

Results The results of the immunohistochemical and special staining are summarized in Table 1. CASE 1

The tumor cells had formed small nests, infiltrating toward the muscle layer of the tongue, and contained an abundance of brown pigmented granules (Fig 3A). Dendritic cells with pigmented granules were also found intermingled with the neoplastic cells. The pigmented granules were identified as melanin using the Fontana-Masson silver impregnation method (Fig 3B). Pigmentation of melanin was not noted in the adjacent normal epithelium. Melanin pigments were present in the cytoplasm of the neoplastic cells and keratin pearls. Infiltrating tumor nests were strongly positive for high-molecular-weight keratin and were negative for low-molecular-weight keratin. Melanocytes with elongated dendritic processes were distrib-

uted among the neoplastic cells. The dendritic melanocytes were strongly positive for Melan A, HMB-45 (Fig 3C,D), and S100; however, a large number of the melanocytes did not appear to be tumor cells. Table 1. IMMUNOHISTOCHEMICAL AND SPECIAL STAIN RESULTS

Variable Epithelial cells FM S100 HMB-45 Melan A LMWK HMWK Melanocytes FM S100 HMB-45 Melan A LMWK HMWK

Case 1

Case 2

Case 3

Negative Negative Negative Negative Positive Negative

Negative Negative Negative Negative Positive Negative

Negative Negative Negative Negative Positive Negative

Positive Positive Positive Positive Negative Negative

Positive Positive Positive Positive Negative Negative

Positive Positive Positive Positive Negative Negative

Positive Control

Positive Positive

Abbreviations: FM, Fontana Masson Silver; LMWK, low-molecularweight keratin; HMWK, high-molecular-weight keratin. Mikami et al. Pigmented Squamous Cell Carcinoma of Oral Mucosa. J Oral Maxillofac Surg 2012.

1236

PIGMENTED SQUAMOUS CELL CARCINOMA OF ORAL MUCOSA

FIGURE 3. Case 1. Proliferation of melanocytes within tumor. Original magnification ⫻400. A,B, Tumor nests contained abundance of melanin granules (A, hematoxylin and eosin stain; B, Fontana and Masson stain). Immunohistochemical staining showing C, Melan A-positive and D, HMB-45–positive immunoreaction. Melanin-containing premature and mature melanocytes with dendritic processes in tumor parenchyma. Mikami et al. Pigmented Squamous Cell Carcinoma of Oral Mucosa. J Oral Maxillofac Surg 2012.

CASES 2 AND 3

Cases 2 and 3 showed similar histologic features. The epithelium was composed of markedly atypical squamous cells with dyskeratosis, large hyperchromatic nuclei, and abnormal mitoses (Figs 4A, 5A). Fontana-Masson staining showed an abundance of melanin pigments distributed mainly within the epithelial tissue (Figs 4B, 5B). Melanin granules were present in the cytoplasm of the neoplastic squamous cells. In the pigmented lesion, numerous melanocytes with elongated dendritic processes were dispersed among the squamous cells from the surface to the basal region of the epithelium; however, no melanin granules were observed in the infiltrating tumor nests. The epithelial components, including the infiltrating tumor nests, were strongly positive for high-molecular-weight keratin and were negative for low-molecular-weight keratin. The dendritic melanocytes were strongly positive for Melan A, HMB-45 (Figs 4C,D; 5C,D), and S100. The distri-

bution of melanocytes in the stroma was localized under the epithelium.

Discussion PSCC is a rare type of SCC and has been reported previously in the skin,3,4,7-14 oral mucosa,1,2,15,17,19,20,22 uterine cervix,5 and conjunctiva.6,16,18,21 Although SCC is the most observed malignant tumor type in the oral region, to our knowledge, 16 cases of PSCC have been reported in 8 different studies, including the present cases (Table 2). Of these 16 cases, 6 were located in the tongue,19,20,22 5 in the gingiva,1,15,17,20 2 in the mouth floor,19 and 1 each in the soft plate,19 hard plate,2 and buccal mucosa. The frequency of PSCC at each site is similar to that of common SCC in the oral mucosa. The PSCC cases seemed to progress more slowly and have a better prognosis than common SCC.3,4,7,9,12 In our case 2, the observed lesion had been present for 5 to 6 years and had also slowly

1237

MIKAMI ET AL

FIGURE 4. Case 2. Proliferation of melanocytes within tumor. A,B, Abundant content of melanin granules distributed mainly within epithelial tissue (A, hematoxylin and eosin; B, Fontana and Masson; original magnification ⫻100). Immunohistochemical staining showing C, Melan A-positive and D, HMB-45–positive immunoreaction. Dendritic cells with pigmentation found intermingling with tumor cells. Original magnification ⫻400. Mikami et al. Pigmented Squamous Cell Carcinoma of Oral Mucosa. J Oral Maxillofac Surg 2012.

enlarged during that period. Metastasis was reported in 1 case,13 and our case 3 is the first report of recurrence. The histopathologic differential diagnosis of oral mucosal lesions with dark pigmentation includes melanin pigmentation with or without syndromes, pigmented nevus, and malignant melanoma. The histologic features of these diseases generally differ from PSCC in terms of the overall morphology. Clinically, PSCC is not always accompanied by macroscopically visible pigmentation.19,20 However, when examined histologically, melanin pigments are found in abundance with numerous melanocytes and are interspersed between the tumor cells. Of the 16 reported cases of PSCC, 11 showed macroscopic dark pigmented lesions,1,2,15,16,19,20,22 and in the other 5 cases, pigmentation was only detected microscopically.19,20 Macroscopic pigmentation requires larger concentrations of melanin pigments within the superficial area of the lesion than in the infiltrating tumor nests or

stroma. Mathews et al13 reported a case of a melanocyte colonization of SCC nodal metastasis arising from the nasal cavity. In that particular case, cervical lymph nodes showed metastatic SCC with an abundance of pigment granules within the cytoplasm of the neoplastic cells. Melanocytes synthesize melanin granules in the form of melanosomes and transfer them to the adjacent keratinocytes by a dendritic process.20 Jauregui and Klintworth21 suggested that the neoplastic cells obtain melanin granules from melanocytes. In previously reported cases, melanocytes were found intermingled with the neoplastic cells.1-22 Melanin granules were also found in the cytoplasm of the neoplastic epithelial cells.1,4-6,11,13,15,16,18,21 In the present 3 cases, we observed neoplastic cells that contained melanin granules in their cytoplasm. The distribution of melanin granules was consistent with that of neoplastic cells in cases 1 and 2. These facts support the hypothesis of Jauregui and Klintworth21 and

1238

PIGMENTED SQUAMOUS CELL CARCINOMA OF ORAL MUCOSA

FIGURE 5. Case 3. Proliferation of melanocytes within tumor. Original magnification ⫻400. A,B, Atypical squamous cells with large or small hyperchromatic nuclei observed (A, hematoxylin and eosin; B, Fontana and Masson). Immunohistochemical staining showing C, Melan A-positive and D, HMB-45–positive immunoreaction. Numerous melanocytes within mucosal epithelium were strongly stained. Mikami et al. Pigmented Squamous Cell Carcinoma of Oral Mucosa. J Oral Maxillofac Surg 2012.

also suggest that there are factors from the carcinoma cells that induce the melanocytes to increase melanin production. Satomura et al2 demonstrated that stem cell factor and endothelin-1 are associated with the stimulation of melanocytes and hyperpigmentation in SCC, using immunohistochemical methods. Matsumoto et al9 reported a case of PSCC of the scrotum, in which a lentiginous lesion was found adjacent to the tumor that had partly incorporated the lentigo. In our case 3, melanin granules were observed in both the tumor and the adjacent normal epithelium. Although a dark pigmentation with erythema was also seen on the hard plate, it was independent of the lesion on the buccal mucosa. These 2 cases suggest that PSCC can occur from the mucosal epithelium, which originally showed hyperpigmentation of melanin. In conclusion, the present report has described 3 cases of PSCC of the oral mucosa that originated on the tongue, mouth floor, and buccal mucosa. Together with previously reported cases, there appear

Table 2. REPORTED CASES OF PSCC OF ORAL MUCOSA

Investigators 22

Patakas et al Ide et al20

Dunlap et al19

Modica et al17 Kuwabara et al15 Satomura et al2 Lisboa et al1 Present study

Age (yr) Gender 47 47 30 59 44 52 55 55 49 56 81 76 57 40 49 78

Male Male Male Male Female Male Female Female Male Female Female Male Female Male Female Female

Site Tongue Tongue Tongue Gingiva Gingiva Tongue Soft plate Tongue Floor Gingiva Gingiva Hard plate Gingiva Tongue Floor Buccal mucosa

Clinically Visible Pigmentation Yes Yes No No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes

Mikami et al. Pigmented Squamous Cell Carcinoma of Oral Mucosa. J Oral Maxillofac Surg 2012.

MIKAMI ET AL

to be several types of PSCC, with or without macroscopic pigmentation and localized or nonlocalized pigmentation within the lesion. In general, PSCC appears to have a better prognosis than conventional SCC; however, reports of more cases are needed to provide additional conclusive data on the prognosis and biologic features of PSCC of the oral mucosa. PSCC could have the same level of malignancy as conventional SCC, although the pigmentation allows patients to become aware of the diseased condition of the mucosa. Acknowledgment The authors thank the Department of Central Clinical Laboratory of the Iwate Medical University Hospital for their expert technical assistance.

References 1. Lisboa CJ, Cazal C, Gomes HAC, et al: Pigmented oral squamous cell carcinoma: A case report and brief review of the literature. Int J Surg Pathol 17:153, 2009 2. Satomura K, Tokuyama R, Yamasaki Y, et al: Possible involvement of stem cell factor and endothelin-1 in the emergence of pigmented squamous cell carcinoma in oral mucosa. J Oral Pathol Med 36:621, 2007 3. Satter EK: Pigmented squamous cell carcinoma. Am J Dermatopathol 29:486, 2007 4. Terada T, Yamagami J, Fugimoto A, Tanaka K, Sugiura M: Pigmented squamous cell carcinoma of the cheek skin probably arising from solar keratosis. Pathol Int 53:468, 2003 5. Masuzawa N, Kishimoto M, Takahashi Y: Pigmented squamous cell carcinoma of the uterine cervix. Int Gynecol Pathol 22: 285, 2003 6. Shields JA, Shields CL, Eagle RC Jr, et al: Pigmented conjunctival squamous cell carcinoma simulating a conjunctival melanoma. Am J Ophthalmol 32:104, 2001 7. Morgan MB, Maribona JL, Miller RA, et al: Pigmented squamous cell carcinoma of the skin: Morphologic and immunohistochemical study of five cases. J Cutan Pathol 27:381, 2000

1239 8. Chapman MS, Quitadamo MJ, Perry AE: Pigmented squamous cell carcinoma. J Cutan Pathol 27:93, 2000 9. Matsumoto M, Sonobe H, Takeuchi T, et al: Pigmented squamous cell carcinoma of the scrotum associated with a lentigo. Br J Dermatol 141:132, 1999 10. Kamiya M, Maehara R, Iizuka S, et al: Pigmented squamous cell carcinoma with dendritic melanocyte colonization in the external auditory canal. Pathol Int 49:909, 1999 11. Umlas J, Liteplo M, Ucci A: Squamous cell carcinoma in situ of the skin containing premelanozomes, with melanocytic colonization of the tumor. Hum Pathol 30:530, 1999 12. Jurado I, Saez A, Luelmo J, et al: Pigmented squamous cell carcinoma of the skin: Report of two cases and review of the literature. Am J Dermatopathol 20:578, 1998 13. Mathews A, Abraham EK, Amman S, Nair MK: Pigmented squamous cell carcinoma of nasal cavity. Histopathology 33:184, 1998 14. Kossard S, Cook D: Pigmented squamous cell carcinoma with dendritic melanocytes. Aust J Dermatol 38:145, 1997 15. Kuwabara H, Ueda H, Miyaguchi M, et al: Pigmented squamous cell carcinoma of the alveolar ridge in the oral mucosa. Oral Surg Oral Med Oral Pathol 77:61, 1994 16. Kremer I, Sandbank J, Weinberger D, Rotem A, Shapiro A: Pigmented epithelial tumours of the conjunctiva. Br J Ophthalmol 76:294, 1992 17. Modica LA, Youngberg GA, Avila FO: Melanocyte colonization of an oral carcinoma. Histopathology 17:477, 1990 18. Salisbury JA, Szpak CA, Klintworth GK: Pigmented squamous cell carcinoma of the conjunctiva. A clinicopathologic ultrastructural study. Ophthalmology 90:1477, 1983 19. Dunlap CL, Tomichi CE: Melanocytes colonization of oral squamous cell carcinoma. Oral Surg Oral Med Oral Pathol 52:524, 1981 20. Ide F, Kusuhara S, Ohnuma H, et al: Pigmented squamous cell carcinoma of the oral mucosa—With special reference to the role of non-keratinocytes in tumors and tumorous conditions. J Nippon Univ Sch Dent 23:1, 1981 21. Jauregui HO, Klintworth GK: Pigmented squamous cell carcinoma of cornea and conjunctiva: A light microscopic, histochemical, and ultrastructural study. Cancer 38:778, 1976 22. Patakas B, Hecker R, Kramer HS: Report on an oral, pigmented squamous cell carcinoma. Int J Oral Surg 3:445, 1974