Abstract
Purpose Radiolucent neoplasms can be identified on dental radiographs in asymptomatic and symptomatic individuals. Examples of these lesions include dentigerous cyst, radicular cyst, odontogenic keratocyst, and ameloblastoma. Many of these lesions require a histologic examination to render the definitive diagnosis. In terms of the ameloblastoma, there are four distinct types of this tumor. These include the conventional ameloblastoma, unicystic ameloblastoma (UA), extraosseous/peripheral ameloblastoma, and metastasizing ameloblastoma. The purpose of this report is to present a case report of a unicystic ameloblastoma found in a 30-year-old female who presented to a general dental practice with a chief complaint of pain and swelling in the mandibular left third molar region. Further evaluation and eventual surgical excision were delayed due to misdiagnosis and delay in performing the biopsy. The definitive diagnosis for this lesion was a benign unicystic ameloblastoma (UA). Due to the size of the defect, the patient required a partial mandibulectomy, reconstructive surgery and placement of two dental implants. While the long-term prognosis for this patient is good, regular surveillance is needed as UA neoplasms have a high recurrence rate. This case study emphasizes the need for oral health care professionals to be vigilant in identifying signs and symptoms of oral disease to support early and accurate diagnosis.
- radiolucent neoplasms
- unicystic ameloblastoma
- odontogenic myxoma
- odontogenic keratocyst
- calcifying odontogenic cysts
INTRODUCTION
One of the most common benign odontogenic tumors of the jaw is the ameloblastoma.1 This tumor is slow-growing, but locally invasive affecting the mandible or maxilla. These tumors tend to have a high recurrence rate and a metastatic potential similar to malignant tumors.1 According to the fourth edition of the World Health Organization Classification of Head and Neck Tumors, there are four known types of this pathosis: conventional ameloblastoma, unicystic ameloblastoma (UA), extraosseous/peripheral ameloblastoma, and metastasizing ameloblastoma.2
Conventional ameloblastoma tumors typically present within the 30–60-year age group with an average age of 35 years and a slight male preponderance.1 They present most commonly within the mandible, predominantly in the posterior region and sometimes in the presence of an unerupted third molar.1 Pain, malocclusion, facial deformity, soft tissue invasion, and loosening of teeth are signs and symptoms of this neoplasm.3 Histologic patterns of ameloblastoma vary with some exhibiting a single histologic subtype including a palisading of columnar cells in a pattern similar to that of ameloblasts of the enamel organ.4 Another variation is the budding of tumor cells in a pattern resembling tooth development.4 The definitive diagnosis of ameloblastoma is established by biopsy as none of the radiological features are pathognomonic for this tumor. Treatment for ameloblastomas is wide surgical excision. Conservative approaches such as curettage, enucleation, and marsupialization result in a high recurrence rate.1 Long-term follow-up is recommended because more than 50 percent of recurrences occur within five years of the initial surgical intervention.5-7
Unicystic ameloblastomas are benign but locally aggressive tumors of epithelial origin. The UA appears more frequently in the second or third decade of life with no apparent sexual or racial predilection.8 These cystic lesions show gross clinical and radiographic features similar to a mandibular cyst. The tumors may arise from pre-existing dentigerous cysts or dental follicles.9 Histological examination reveals a typical ameloblastomatous epithelial lining with or without luminal or mural growth.10 A review of 63 UA patients reported an average duration of 8.6 months from the initial presentation of symptoms, such as pain and paresthesia, to the onset of mandibular swelling.11 Treatment options for UA range from conservative enucleation to radical procedures including marginal or segmental resection with subsequent bone reconstruction.12,13 Radical approaches may be more invasive; however, they significantly reduce the risk of recurrence compared to conservative approaches.12,13 A retrospective study of UA at one institution noted a high recurrence rate of 30.5% with surgical enucleation compared to a low recurrence rate of 3.6% with resection.14
The extraosseous/peripheral ameloblastoma most often occurs in the gingiva and less commonly in the buccal mucosa. This type of ameloblastoma is seen in individuals between 40 and 60 years of age. They are benign, nonaggressive lesions that typically do not invade the underlying bone. Wide local excision is the recommended treatment with a recurrence rate of 9 to 20 percent.1,4
Metastasizing ameloblastoma are rare but tend to occur in young adults and in males more than females. This lesion occurs in the mandible more commonly than the maxilla. Metastasis tends to occur in the lungs and lymph nodes followed by the skull, liver, spleen, and kidneys. The prognosis for this neoplasm is poor with 40% having a 2-year survival rate.1
The purpose of this clinical case study is to discuss a radiolucent lesion found in a 30-year-old female who presented to a general dental practice with the chief complaint of pain and swelling in the left mandibular third molar region. This case study highlights the critical role of oral health providers in recognizing early signs and symptoms of oral disease, emphasizing their responsibility in facilitating timely and accurate diagnosis to improve patient outcomes.
CASE DESCRIPTION
A 30-year-old female attended a northwestern general dental practice for routine adult prophylaxis and biannual dental examinations with a chief complaint of pain and swelling in the left mandibular molar region. Significant findings from the medical history included the current use of oral contraceptives, an allergic reaction to Vicryl sutures following childbirth in 2022, and a Methicillin-resistant Staphylococcus aureus (MRSA) infection in childhood. Clinical examination revealed a history of orthodontic treatment with a permanent retainer on the lingual surfaces of the mandibular anterior teeth, extraction of four wisdom teeth, and composite and amalgam restorations localized to the posterior teeth. Extraction of the wisdom teeth was completed in December 2023, preceding the development of a mass at the site of tooth #17.
Upon examining the patient intraorally, a diagnosis of caries disease in the mandibular posterior region was made based on visual findings; however, the patient was uncertain which tooth was involved. At the second appointment scheduled for restorative treatment, the patient expressed concern that the lesion had grown and that she had persistent pain in the affected area. A periapical image of the painful region was taken but was undiagnostic because the image receptor was not placed far enough posteriorly to capture the lesion. No explanation was provided for why the image was not retaken. At the patient’s request, a prescription for amoxicillin was provided on the premise that the pain was related to an ongoing dental infection. The patient continued to have pain at the follow-up appointment and was subsequently referred to a periodontist for further evaluation.
Rather than scheduling an appointment with a periodontist, the patient sought a second opinion from another general dentist. At this time, a panoramic image was taken (Figure 1). Findings revealed a well-circumscribed radiolucency of the left mandibular molar region at the site where tooth #17 had been extracted. The patient was referred to an oral surgeon for a biopsy.
Unilocular lesion with well-defined borders in the third molar region of the mandibular left quadrant.
The patient was examined by the oral surgeon during late January 2024, and a cone beam computed tomography (CBCT) scan was ordered. An advantage to using a CBCT is the replicable measurements of radiodensity that are presented in a scale of values or Hounsfield units.15 The CBCT scan occurred on January 26, 2024 and revealed a 2.54 cm osseous defect (Figure 2). Cadaver bone was placed in the defect by the oral surgeon. At the time of the two-week post-operative appointment, the patient presented with an allergic response to the sutures and localized infection at the surgical site. The wound began to dehisce and cadaver bone was exposed.
Axial view of the lesion on a CBCT image.
The patient returned to the oral surgeon for a second follow-up appointment for evaluation of wound healing and was informed that the mass was growing aggressively. The oral surgeon diagnosed the lesion as a traumatic bone cyst. No biopsy or further treatment was recommended or performed at that time. In July 2024 the patient returned to the oral surgeon due to persistent pain and swelling with pain extending to the left arm. As the mass had doubled in size since her previous visit, the surgeon performed a biopsy and referred her to an endodontist who examined the patient and noted her posterior teeth were vital. No further treatment was indicated for the posterior teeth adjacent to the mass.
Differential diagnosis
Given the clinical and radiographic presentations, the differential diagnosis included odontogenic myxoma, odontogenic keratocyst (OKC), and calcifying odontogenic cyst (COC). The odontogenic myxoma is a benign tumor of the jaws arising from the mesenchymal portion of the tooth germ.8 These lesions can be found throughout the body, including the arm, and are present in patients 10 to 50 years with the average age of approximately 30 years, with a higher prevalence among females.16,17 Odontogenic myxomas tend to displace teeth and cause external root resorption and pain.4,16 These tumors are often slow-growing, central tumors of the jaws, primarily in the posterior mandible. Although benign, they can be locally invasive.18 The classic radiographic presentation is a unilocular or multilocular radiolucency with well-defined margins.8 Treatment consists of surgical excision ranging from simple enucleation to radical approaches.8.16 However, conservative management with excision, curettage, and peripheral ostectomy preserves vital structures and maintains facial contour.17 These lesions have a moderate recurrence rate and repeated surgical intervention is often needed.16,18
The odontogenic keratocyst (OKC), also referred to as a keratocystic odontogenic tumor (KCOT), is a benign developmental tumor that is locally aggressive.19 This tumor is derived from the remnants of a tooth germ or dental lamina. It most often occurs within the 30-50 age range. Swelling is the most common clinical manifestation although some patients may have symptoms of pain, suppuration, and loose teeth. The OKC most often occurs in the ascending ramus and molar region. Radiographs reveal round or oval radiolucencies with well-defined borders. Odontogenic keratocysts tend to have a high recurrence rate due to the aggressive biological nature of the tumor and the surgical method used.19 Certain treatments help prevent recurrence including the use of 5-fluorouracil, peripheral ostectomy or resection, and enucleation and curettage.20 Of note, the OKC has the potential for malignant transformation with pain and swelling as common signs.19
The calcifying odontogenic cyst, also referred to as the calcifying cystic odontogenic tumor, is a developmental lesion that arises from odontogenic epithelium. It has been described as a cyst with an ameloblastoma-like epithelium that contains calcifications and ghost cells.21 This lesion can occur in any location of the oral cavity although most occur in the anterior maxilla and mandible.22 Most COC occur between 20-59 years of life and are asymptomatic. They appear as unilocular or multilocular radiolucency with root resorption and divergence as common findings. In approximately one-third of cases, radiographic findings are associated with an impacted tooth. The multilocular form may have the presence of calcifications.21,22 Surgical excision or enucleation is the recommended treatment. The prognosis is good as there tend to be few recurrences; however, long-term follow-up is recommended.22
Diagnosis and Treatment
Approximately 7 months after the initial presentation, an oral surgeon performed a biopsy of the mass in the left posterior mandible. At that point, the tumor had reached 6.35 cm. The biopsy included nine areas of the head and neck region including: lymph node left neck level 1B, lymph node left neck level 2, left mandible segmental mandibulectomy, posterior marrow margin (extended), anterior marrow margin (extended), left buccal mucosal margin (extended), left lower lip margin (extended), floor of mouth margin (extended), anterior alveolar ridge margin (extended). Findings revealed four enlarged benign lymph nodes at the left submandibular section and three enlarged benign lymph nodes along the left anterior and posterior portions of the upper jugular lymph node chain. A left, segmental mandibulectomy showed a small, 1.524 cm at its greatest dimension, focus of residual ameloblastoma surrounded by abundant peritumoral fibrosis and bony remodeling. The lesion was localized within the trabecular bone, inferior to the third molar area, and extending into the retromolar region. There was no soft tissue or mucosal involvement. The biopsy report indicated a definitive diagnosis of a benign UA.
Once the definitive diagnosis was made, the patient underwent a partial mandibulectomy, fibula free flap reconstruction, and dissection of 27 lymph nodes. Surgical complications included nerve damage resulting in persistent numbness of the left labial commissure. Two dental implants were placed to restore function on the left side. The patient also experienced complications during the recovery period. Sepsis necessitated a second surgical intervention, and the patient required enteral nutrition for one month following surgery. Additionally, the patient developed a cervical abscess, possibly due to a reaction to the sutures used for the mandibulectomy. At the three-month post-operative examination, a panoramic radiograph indicated clear findings. The patient will require evaluations every three months as there is a likelihood of recurrence.
DISCUSSION
Unicystic ameloblastomas are often mistaken for other neoplasms due to their atypical radiographic appearance. Ameloblastomas are relatively common and benign odontogenic tumors, yet as seen in this case, can be very destructive. This case underscores the need for careful evaluation by oral health professionals through the performance of the comprehensive oral examination, recognition of presenting signs and symptoms, differential diagnosis, and a biopsy to determine a definitive diagnosis as the UA can mimic other neoplasms. Dental hygienists should be well educated on atypical oral presentations, the process for making referrals for further evaluation, and how to support patients in their long-term care following diagnosis and treatment. Dental hygiene educators have an opportunity to teach students the importance of screening for abnormalities, creating differential diagnoses, exploring treatment options, and timely referrals to specialists when needed.
This case demonstrates the importance of early detection and diagnosis. Early detection consists of visual inspection, digital palpation of the oral cavity, and the use of adjunctive aids such as radiographic examination and biopsy.24 These procedures assist with identifying benign, premalignant and malignant disorders. Although visual examination is readily available, many lesions are diagnosed at a later stage.24 Hadzic, et al described reasons for late diagnosis in relation to oral cancer; however, the concept applies to all lesions.25 These authors note that many patients lack awareness and ignore symptoms, which is considered “the first loss of time”. Lack of awareness of medical and dental professionals and lack of a timely diagnosis represents the “second loss of time”. The “third loss of time” is the period that occurs from diagnosis to treatment. Reducing these time sequences is critical for successful health outcomes.25 This case describes a lapse of 7 months before a biopsy was performed and appropriate treatment was rendered.
Diagnostic errors occur in the health professions. Examples include misdiagnosis, failure to diagnose, and delayed diagnosis. A review of 182 published case reports in dentistry revealed that 23% of cases were categorized as delayed appropriate treatment, disease progression, or unnecessary treatment associated with misdiagnosis.26 In this case, the patient presented for evaluation and experienced a delay in diagnosis. She was not provided a differential diagnosis, and the initial clinical and radiographic examinations were inadequate. A biopsy was not performed for an extended period of time. Vigilance on the part of dentists and dental hygienists is imperative to reduce the incidence of diagnostic errors and potential adverse events for the patient.
Further, diagnostic errors can negatively impact patient quality of life. In a study of patient experiences associated with dental diagnostic failures, patients reported experiencing difficulty eating and communicating, pain, trouble sleeping, emotional distress and mental health challenges including anxiety, stress, and depression.27 Many patients reported developing an overall negative perception of dentists as a result of these experiences. However, confidence was often restored when patients found a different dentist who identified and provided treatment for the misdiagnosis.27 In the case of the patient with a UA, she experienced persistent and worsening pain impacting her quality of life. Even though the patient encountered post-surgical complications, she remained positive about the diagnosis and prognosis. She continues to be vigilant in attending follow-up protocols.
Dental hygienists play a key role in the continuity of care by monitoring oral health, reinforcing post-treatment instructions, and providing ongoing support and education to help patients maintain optimal outcomes. Through regular follow-up appointments, dental hygienists can identify potential complications early and coordinate care with the dental team, ensuring the patient’s recovery and long-term oral health are actively supported.
CONCLUSION
This case underscores the critical role of early recognition and appropriate management in the diagnosis of jaw lesions such as unicystic ameloblastoma. Despite its benign classification, UA demonstrates locally aggressive behavior and poses significant risks if left untreated or misdiagnosed. In this case, the delay in diagnosis and inadequate early interventions contributed to increased patient morbidity and a more extensive surgical outcome. This case report emphasizes the importance of thorough clinical and radiographic evaluations, timely biopsy, and interdisciplinary collaboration in achieving accurate diagnosis and favorable treatment outcomes.
IMPLICATIONS FOR DENTAL HYGIENE PRACTICE
Dental hygienists should be educated to recognize atypical oral findings and advocate for further diagnostic evaluations when lesions do not resolve or present with unusual features.
Comprehensive intraoral and extraoral examinations, including palpation and radiographic review, are essential components of routine dental hygiene and dental care to aid in early detection of pathologic conditions.
Effective interpersonal communication and timely referrals are critical when patients present with persistent symptoms beyond the scope of routine dental hygiene intervention.
Footnotes
NDHRA priority area, Client level: Basic science (dental hygiene diagnosis).
DISCLOSURES
The authors have no conflicts of interest to disclose.
- Received December 11, 2025.
- Accepted April 4, 2026.
- Copyright © 2026 The American Dental Hygienists’ Association
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