Ameloblastic carcinoma with metastasis to the parotid gland

Abstract

Ameloblastomas are a rare entity, representing 1% of tumors and cystic lesions of the jaw. 1 A subset of these lesions, termed ameloblastic carcinoma, contain histologic architectural features of ameloblastoma along with malignant cytological features. Ameloblastic carcinomas were re-classified as a separate diagnostic entity by the WHO in 2005. This re-classification separates ameloblastic carcinoma from malignant ameloblastoma, which refers to metastatic ameloblastomas with benign cytologic features. Primary ameloblastic carcinomas are more common; however, cases arising from a pre-existing ameloblastoma, categorized as secondary ameloblastic carcinoma, have been reported. 2,3 A 30-year-old man presented with a right-sided parotid mass. His medical history was significant for nodular sclerosing Hodgkin lymphoma, treated with radiation therapy at the age of 20. He subsequently developed ameloblastic carcinoma of the left mandible extending through the mandible to involve surrounding soft tissue. He underwent resection with adjuvant chemoradiation for his initial tumor at age 24 and a for local recurrence at age 27. Five years following initial diagnosis, he experienced right sided facial swelling over the parotid gland. Fine-needle aspiration of the parotid mass was performed. Diff-Quik® and Papanicolaou stained smears were hypercellular, consisting of numerous single cells and loosely cohesive fragments and clusters of cells (Figure 1). Most cellular fragments displayed a peripheral palisading. Morphologically, the cells were small to intermediate size, basaloid with high nuclear to cytoplasmic ratio, and appeared cuboidal to tall columnar (Figure 2). Rare large cells with clear cytoplasm were present mingled with basaloid cells. Spindle cells were noted on Papanicolaou stain. The nuclei were round to oval with finely granular chromatin containing one or multiple small nucleoli (Figure 3). Nuclear molding, nuclear overlap, and occasional nuclear grooves were better observed with Diff-Quik stain. The cytoplasm was scant to moderate, delicate, and finely vacuolated with indistinct cell borders (Figure 4). Additional cytomorphologic findings included occasional atypical mitotic figures, apoptotic nuclei, small areas of necrosis, and nuclear streaking artifact. A finely granular, vacuolated, gray, and basophilic matrix was seen in Diff-Quik stained smears. These findings, particularly a hypercellular aspirate showing basaloid cells with peripheral palisading, the presence of spindled cells, and nuclear features including molding and fine chromatin, suggest a diagnosis of ameloblastic carcinoma. The differential diagnosis should include lymphoma, small cell carcinoma, HPV-related head and neck squamous cell carcinoma, and a neuroendocrine tumor of the nasopharynx based on the small, loosely cohesive, basaloid cell population seen in this case. 4-7 Ameloblastic carcinoma lacks the prominent lymphoglandular bodies seen in lymphoma, and has a finer chromatin pattern than the "salt and pepper" chromatin seen in small ce...

Rare solitary pituitary metastasis of maxillary ameloblastic carcinoma: illustrative case

“… 12 The lung and regional lymph nodes are the most common sites of AC metastasis, and later to the liver, bone, brain, kidney, small intestine, and myocardium, but pituitary metastasis has never been reported. 5 , 6 , 13 Distant metastasis of AC has been associated with a significant decrease in overall survival. 14 …”

“…However, the aggressive behavior of AC tends to result in local recurrence, metastasis to other distant organs or regional lymph nodes, and direct invasion into skull base structures, implying a poor prognosis. [5][6][7] The etiology, clinical course, and optimal management of this very rare disease remain unclear, especially in patients with metastasis. We describe an unusual case of AC with hematogenous metastasis to the pituitary gland without direct invasion and local recurrence at the primary site, which was successfully managed with cytoreductive safe resection following stereotactic radiotherapy (SRT) using the CyberKnife system.…”

Rare Ameloblastic Carcinoma Metastasis to the Cervical Spine: A Case Report

“…19 The most common location for metastases is the lung; however, cases have been reported of spread to the skull base, parotid gland, liver, and bone. 8,9,[25][26][27] Unfortunately, prognosis is poor even with multimodal therapy. 15,19 Rare case studies have reported the use of chemotherapy without consistent success.…”

“…7 AC has poor progression-free survival and can metastasize widely. 8,9 There have been case reports of AC extending to the skull base with intracranial extension [10][11][12][13] ; however, to date there have been no reports of spinal column involvement. Herein, we present the first reported case of ABBREVIATIONS: AC, ameloblastic carcinoma; C3, cervical 3; PBT, proton beam therapy invasive AC metastasis to a cervical vertebral body causing kyphotic deformity and significant spinal cord compression requiring surgical resection with ventral and dorsal stabilization.…”

Metastasising ameloblastoma or ameloblastic carcinoma? A case report with mutation analyses

“…The clinical features of AC are similar to those of ameloblastoma [ 12 ]; the histopathological features include the lack of differentiation, hypercellularity, a high mitotic index, vascular invasion and neural invasion. Metastasis into cervical lymph nodes or other sites including vertebrae, pleura, the skull, the parotid glands, the diaphragm and the liver are typical for AC [ 17 , 18 ]. Due to the limited understanding of this malignancy, no standard of care has been established yet; therefore, care largely depends on the clinical features of the specific patient and procedures in the particular hospital.…”