Indian Journal of Pathology and Microbiology
Home About us Instructions Submission Subscribe Advertise Contact e-Alerts Ahead Of Print Login 
Users Online: 4350
Print this page  Email this page Bookmark this page Small font sizeDefault font sizeIncrease font size

  Table of Contents    
Year : 2015  |  Volume : 58  |  Issue : 2  |  Page : 214-216
Primary Merkel cell carcinoma of the oral mucosa in a young adult male: Report of a rare case

1 Department of Pathology and Medical Oncology, Saroj Gupta Cancer Centre and Research Institute, Kolkata, West Bengal, India
2 Medical College, Kolkata, West Bengal, India

Click here for correspondence address and email

Date of Web Publication17-Apr-2015


Merkel cell carcinoma (MCC) is a highly aggressive neoplasm of skin with neuroendocrine differentiation. Primary MCC of the oral mucosa is exceedingly rare and even more unresponsive to therapy. A 15-year-old male presents with gradually increasing painless swelling in right side of the floor of mouth for 6 weeks. Computed tomography of head and neck region showed globular mass (4.6 cm × 1.7 cm) involving right side of the floor of mouth. Fine-needle aspiration from the upper deep cervical node suggested small round cell tumor. A trucut biopsy showed mass composed of trabeculae and nests of tumor cells with high N:C ratio, granular speckled chromatin, scanty to moderate amount of clear vacuolated cytoplasm. Cells were immunoreactive for cytokeratin-20, CD56, c-kit, CD99 and negative for p63, thyroid-transcription factor-1, CDX2, synaptophysin, neuron-specific enolase. Patient was started on chemotherapy with cyclophosphamide, doxorubicin and vincristine. The mass regressed in size and patient underwent wide local excision with pull-through approach. Patient is currently under combined chemoradiation regime and doing well.

Keywords: Chemoradiation, immunohistochemistry, Merkel cell, oral mucosa, young male

How to cite this article:
Roy S, Das I, Nandi A, Roy R. Primary Merkel cell carcinoma of the oral mucosa in a young adult male: Report of a rare case. Indian J Pathol Microbiol 2015;58:214-6

How to cite this URL:
Roy S, Das I, Nandi A, Roy R. Primary Merkel cell carcinoma of the oral mucosa in a young adult male: Report of a rare case. Indian J Pathol Microbiol [serial online] 2015 [cited 2023 Oct 2];58:214-6. Available from:

   Introduction Top

Merkel cell carcinoma (MCC) is the currently preferred term for a distinctive cutaneous malignancy synonymous with primary small cell/neuroendocrine carcinoma (NEC) of skin. They were first described by Toker in 1972, and at that time was named trabecular carcinoma. The name MCC was assigned in 1978 when Tang and Toker found an ultrastructural similarity between these tumor cells and the Merkel cells. MCC very rarely occurs on mucous membranes of the head and neck region. In 1988, the first case report of an oral presentation of MCC was published. [1] Among oral mucosa, various case reports of this tumor arising in mucobuccal fold, labial mucosa, glossopharyngeal, palatal and alveolar mucosa has been reported. Very few cases of this tumor arising in young adults have also been cited. [2],[3]

We report a case of primary MCC arising in floor of the mouth in a young adult male; we will review the literature and discuss the immunohistochemical profile and treatment options.

   Case Report Top

A 15-year-old male presented to us with gradually increasing painless swelling under right side of the floor of mouth below the tongue for 6 weeks and swelling below the right side of jaw for 2 weeks. A globular reddish granular mass (4 cm × 1.5 cm) was noted in floor of mouth involving lingual frenulum and extending upto right alveolar mucosa along with a base of tongue [Figure 1]a. Bilateral submandibular, submental and inguinal lymphadenopathy was noted. Fine-needle aspiration from the upper deep cervical node suggested small round cell tumor. A trucut biopsy from the mass was planned for the tissue diagnosis.
Figure 1: (a) 15-year-old adult male with reddish granular mass in floor of mouth (b) gross picture of wide local excision of mass, cut section homogeneous white (c) preoperative computed tomography (CT) scan of head neck showing mass in floor of mouth (d) postchemotherapy CT scan showing mass regressed

Click here to view

Histopathology showed a tumor mass predominantly localized in dermis with superficial stratified squamous epithelium being free [Figure 2]a. The tumor is composed of trabeculae and nests of tumor cells with high N:C ratio, granular speckled chromatin, scanty to moderate amount of clear vacuolated cytoplasm [Figure 2]b. A provisional diagnosis of poorly differentiated carcinoma was made, and immunohistochemistry was suggested. Cells were immunoreactive for cytokeratin-20 (CK-20) [Figure 2]c, CD56 [Figure 2]d, c-kit, CD99 and negative for p63, thyroid-transcription factor-1 (TTF-1), CDX2, synaptophysin, neuron-specific enolase (NSE). Computed tomography (CT) abdomen showed no lymphadenopathy or space occupying lesions in the liver. Chest X-ray was clear. In view of metastatic disease, patient was started on chemotherapy with cyclophosphamide, doxorubicin and vincristine. The mass regressed in size in postchemo CT scan [Figure 1]c and [Figure 2]d. He subsequently underwent wide local excision with pull-through approach [Figure 1]b with a 2.5 cm free margin. Histopathological examination of tumor mass corroborated with the trucut diagnosis. All the margins were free. Neck dissection showed tumor deposit in 5 of 14 lymph nodes. His postoperative period was uneventful, and he was planned to put on combined chemoradiotherapy regime (repeat 3 cycles of cyclophosphamide, doxorubicin and vincristine, followed by radiation of 60 Gy in 30 fractions over 6 weeks). The patient is currently doing well after 9 months of diagnosis.
Figure 2: (a) photomicrograph of mass predominantly localized in dermis (H and E, ×200) (b) photomicrograph of trabeculae of tumor cells with granular chromatin and clear cytoplasm (H and E, ×400) (c) cytokeratin-20 (CK-20) positivity in tumor cell (CK-20, ×400) (d) CD56 positivity in tumor cell (CD56, ×200)

Click here to view

   Discussion Top

In 1875, the German anatomist and pathologist Merkel first described a type of cell in the basal layer of the epidermis. Merkel cells occur in the basal epidermal layer, hair follicles, and oral mucosa, as complexes with sensory axons. They have neuroendocrine granules, rigid spinous processes, and desmosomal junctions with each other and with keratinocytes. There has been controversy over the origin of Merkel cells. Most recently conclusive evidence for a neural crest origin has been obtained. [4]

Primary malignant oral tumors that show a neuroendocrine phenotype display histomorphologic heterogeneity thereby giving rise to a spectrum of lesions. These lesions can be divided into NECs of small cell or nonsmall cell type. The former is further subdivided into the Merkel cell type or the pulmonary type while the latter includes atypical carcinoid tumor and large cell NEC. [5] It remains to be determined whether histologic categorization of the remaining tumor subtypes is predictive of patient survival.

There is overall male predominance in most of the case reports in mucosal MCC cases. In a recent study, Koljonen et al. found a strong female predominance in cutaneous MCC while other studies show an even rate or a slight male predominance. [6]

The histopathologic differential diagnosis includes basal cell carcinoma, melanoma, lymphoma, eccrine carcinoma, poorly differentiated squamous cell carcinoma, metastatic neuroblastoma, primary peripheral primitive neuroectodermal tumor and metastatic NEC.

Immunohistochemically, MCC shows epithelial and neuroendocrine differentiation. CK-20 is a sensitive and quite specific marker for MCC. CK-20 is useful in combination with TTF-1 to differentiate between MCC (CK-20 positive, TTF-1 negative) and small cell carcinoma of the lung (<10% CK-20 positive, TTF-1 positive). Markers of neuroendocrine differentiation include chromogranin a, synaptophysin, NSE. MCC also expresses CD117, the KIT receptor tyrosine kinase and in approximately a third of cases, CD99.

Merkel cell carcinoma has an aggressive course with early lymphatic and hematogenous spread. Since the tumor often remains asymptomatic for some time, spread has occurred in most cases at the time of diagnosis. In cutaneous cases of MCC, a local recurrence rate of 11-45% is reported. About 55-60% of the cases develop positive lymph nodes. Distant metastases, mostly to lung, liver, bones and brain, occur in about 35% of the patients. Survival at 3 years is reported at 30-70%. Vigneswaran et al. did a review of the literature in 1992 and included 12 cases of MMC, 2 oral and 10 peri-oral tumors. [7] None of these patients reached a survival of 3 years.

Resection of a cutaneous MCC with a wide margin of 2-3 cm is recommended, in combination with an elective lymph node dissection. [8] Because of the aggressive behavior, postoperative radiotherapy is generally recommended with a dose of 50-60 Gy in 25-30 fractions over 5-6 weeks in case of negative margins. [9] The tumor appears to be fairly radiosensitive, and radiotherapy is sometimes given as the primary modality with curative intent. When distant metastases occur, chemotherapy should be considered. Voog et al. reviewed the literature on the effect of chemotherapy on distant metastasis and on locally advanced cases of MCC. [10] They showed response rate to first-line chemotherapy was 61% but declined to 57% for patients with metastasis. They concluded the tumor to be chemosensitive but not chemocurable.

Merkel cell carcinoma of the oral mucosa is a challenging entity both for the pathologists and the clinicians. Exclusion of secondary extensions is essential for the diagnosis and current treatment options include combined chemoradiation. Sadly, the prognosis is yet to improve.

   References Top

Mir R, Sciubba JJ, Bhuiya TA, Blomquist K, Zelig D, Friedman E. Merkel cell carcinoma arising in the oral mucosa. Oral Surg Oral Med Oral Pathol 1988;65:71-5.  Back to cited text no. 1
Prabhu S, Smitha RS, Punnya VA. Merkel cell carcinoma of the alveolar mucosa in a young adult: A rare case report. Br J Oral Maxillofac Surg 2010;48:48-50.  Back to cited text no. 2
Inoue T, Shimono M, Takano N, Saito C, Tanaka Y. Merkel cell carcinoma of palatal mucosa in a young adult: Immunohistochemical and ultrastructural features. Oral Oncol 1997;33:226-9.  Back to cited text no. 3
Halata Z, Grim M, Bauman KI. Friedrich Sigmund Merkel and his "Merkel cell", morphology, development, and physiology: Review and new results. Anat Rec A Discov Mol Cell Evol Biol 2003;271:225-39.  Back to cited text no. 4
Mahomed F. Neuroendocrine cells and associated malignancies of the oral mucosa: A review. J Oral Pathol Med 2010;39:121-7.  Back to cited text no. 5
Koljonen V, Böhling T, Granhroth G, Tukiainen E. Merkel cell carcinoma: A clinicopathological study of 34 patients. Eur J Surg Oncol 2003;29:607-10.  Back to cited text no. 6
Vigneswaran N, Müller S, Lense E, Stacey B, Hewan-Lowe K, Weathers DR. Merkel cell carcinoma of the labial mucosa. An immunohistochemical and ultrastructural study with a review of the literature on oral Merkel cell carcinomas. Oral Surg Oral Med Oral Pathol 1992;74:193-200.  Back to cited text no. 7
Lehrer MS, Hershock D, Ming ME. Merkel cell carcinoma. Curr Treat Options Oncol 2004;5:195-9.  Back to cited text no. 8
Eich HT, Eich D, Staar S, Mauch C, Stützer H, Groth W, et al. Role of postoperative radiotherapy in the management of Merkel cell carcinoma. Am J Clin Oncol 2002;25:50-6.  Back to cited text no. 9
Voog E, Biron P, Martin JP, Blay JY. Chemotherapy for patients with locally advanced or metastatic Merkel cell carcinoma. Cancer 1999;85:2589-95.  Back to cited text no. 10

Correspondence Address:
Dr. Ayandip Nandi
48/7, Patuapara Lane, P.O. Serampore, Hooghly - 712 201, West Bengal
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0377-4929.155318

Rights and Permissions


  [Figure 1], [Figure 2]

This article has been cited by
1 Merkel Cell Carcinoma of the Maxillary Sinus: An Unusual Presentation of a Common Tumor
Jesse D. Sheldon, Abberly A. Lott Limbach
Head and Neck Pathology. 2021; 15(2): 691
[Pubmed] | [DOI]
2 Primary small cell neuroendocrine carcinoma of the right posterior tongue
Yu Zhou, Hang-Cheng Zhou, Hui Peng, Zhi-Hong Zhang
World Journal of Meta-Analysis. 2020; 8(4): 285
[Pubmed] | [DOI]
3 MicroRNAs as Potential Biomarkers in Merkel Cell Carcinoma
Aelita Konstantinell,Dag Coucheron,Baldur Sveinbjørnsson,Ugo Moens
International Journal of Molecular Sciences. 2018; 19(7): 1873
[Pubmed] | [DOI]
4 Primary Merkel cell carcinoma of the earlobe in a young healthy man
Non Hyeon Ha,Sue Kyung Kim,Yoo Seob Shin,Sue Min Kim
Archives of Craniofacial Surgery. 2018; 19(3): 205
[Pubmed] | [DOI]
5 Merkel Cell Carcinoma of the Buccal Mucosa and Lower Lip
Mohammed N. Islam,Hardeep Chehal,Molly Housley Smith,Sarah Islam,Indraneel Bhattacharyya
Head and Neck Pathology. 2018; 12(2): 279
[Pubmed] | [DOI]
6 Merkel cell carcinoma in an immunosuppressed patient
Heliana Freitas de Oliveira Góes,Caren dos Santos Lima,Maria Cláudia de Almeida Issa,Flávio Barbosa Luz,Luciana Pantaleão,José Gabriel Miranda da Paixão
Anais Brasileiros de Dermatologia. 2017; 92(3): 386
[Pubmed] | [DOI]
7 Small cell carcinoma in the palatal mucosa: A case report
Miwako Sase,Hiroto Itoh,Junichi Hayasaka,Kentaro Hoshi,Tadahide Noguchi,Yoshinori Jinbu,Yoshiyuki Mori
Journal of Oral and Maxillofacial Surgery, Medicine, and Pathology. 2016; 28(6): 493
[Pubmed] | [DOI]
8 Primary retroperitoneal Merkel cell carcinoma: Case report and literature review
Osvaldo A. Quiroz-Sandoval,Mario Cuellar-Hubbe,Leonardo S. Lino-Silva,Rosa A. Salcedo-Hernández,Horacio N. López-Basave,Alejandro E. Padilla-Rosciano,Alberto M. León-Takahashi,Ángel Herrera-Gómez
International Journal of Surgery Case Reports. 2016; 19: 21
[Pubmed] | [DOI]
9 Merkel cell carcinoma – Beast with two Backs
Anjali P. Ganjre,Neeta Bagul,Gargi Sarode
Oral Oncology. 2015; 51(9): 880
[Pubmed] | [DOI]


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Email Alert *
    Add to My List *
* Registration required (free)  

   Case Report
    Article Figures

 Article Access Statistics
    PDF Downloaded149    
    Comments [Add]    
    Cited by others 9    

Recommend this journal