Merkel cell carcinoma is a rare and aggressive malignant primary tumor with neuroendocrine features. This clinical report presents a 75-year-old patient diagnosed in 2016 with an intraoral Merkel cell carcinoma that was surgically treated with a wide local excision. The partial maxillectomy resulted in an Aramany Class II defect, leaving the patient with severe speech and functional limitations. The definitive prosthodontic management of this patient’s condition was achieved by a combination of fixed and removable dental prostheses, including enameloplasty, composite resin restorations, individual surveyed crowns, a mandibular cast metal framework partial denture, and a maxillary obturator prosthesis.
A 75-year old woman presented to the Graduate Prosthodontic clinic of the University of Minnesota in October 2017 with the chief concern: “I want an upper partial and an obturator! I can’t chew properly.” Her medical history included GERD, arrhythmia, sleep apnea, prosthetic joint replacements, HBP, hyperlipidemia, history of seizures, breast cancer (1991), stroke (2005) and intraoral Merkel cell carcinoma (2016) surgically treated with a wide local excision. The partial maxillectomy left the patient with an extensive defect of the left alveolar ridge, hard and soft palate. No adjuvant chemotherapy or radiotherapy was required.
The clinical findings included hypernasality and phonetic limitations, palatal defect (Aramany Class II), post-surgical osteonecrosis, loss of VDO, limited interocclusal space, defective removable partial dentures, partial edentulism, defective restorations #6, 7, 11, extruded #1, generalized marginal gingivitis, localized moderate chronic periodontitis, plaque/subgingival calculus, bilateral lingual tori, and attrition.
Aramany classification: Maxillary defect classification for partially edentulous patients based on the frequency of occurrence of the defect in the population.
Class II: Unilateral resection (keeps anterior and contralateral posterior teeth)
Other classifications: Bidra et al. (2012) recommended a criteria-based description, as it appears more objective for universal use than a classification-based description.
Merkel cell carcinoma (MCC):
A MCC is a rare, rapidly growing and spreading, malignant primary tumor of the skin. Its cells contain cytoplasmic granules that resemble the neurosecretory granules found within the epidermal Merkel cells of the touch receptor regions.
This cancer presents itself as a dome-shaped nodule with a smooth surface and firm texture. It occurs in the skin of the head and neck, with very few intraoral occurrences (4.5%). People over 65 years of age as well as fair-skinned individuals are at a higher risk.
The treatment consisted of a wide local excision, but adjuvant radiotherapy was not found to improve survival. The 5-year survival rate is 64% (75% if localized). Twenty-five percent of MCC patients develop additional malignancies (SCC or adenocarcinoma of the breast) before, concurrent with, or after the diagnosis.
Treatments were divided in two phases. Phase 1 – Initial therapy included SRP and prophylaxis, bilateral mandibular tori removal and enameloplasty #1, 21, 28. Phase 2 – Prosthodontic rehabilitation included composite resin restorations #1B and #11ML, surveyed metal-ceramic crowns #6, 7 at the patient’s current VDO, a maxillary obturator (Aramany Class II) with a lingual plate/metal overlay to re-establish adequate VDO and a mandibular RDP.
The purpose is to restore the mastication, deglutition, speech, and facial contour. Tooth preservation has the greatest impact on success because of its stabilizing effect on prosthetic movements.
Aramany class II design:
- Palatal strap/plate decreases rotational movement and increases vertical support
- Bulb is processed on the framework and remains solid due to its small size
- Engaging the scar band is ideal (retention)
The overall prognosis is fair, with #1 being guarded. The risk of recurrence of the cancer, metastasis, or new primary tumor (5-year survival is 64%) is significant.
Phonetics – Hypernasality:
A maxillectomy will cause hypernasality of the voice as the air escapes through the defect. An obturator plate provides adequate oronasal separation which improves resonance. Therefore, in maxillectomy cases after rehabilitation, nasalance is eliminated and returns to normal.
In regards to reducing hypernasality, the high bulb obturators showed superior results compared to low bulb obturators. In terms of articulation of speech, low bulb obturators function similarly to high bulb obturators.
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