Adenoid cystic carcinoma

Abstract

Adenoid cystic carcinoma is a fairly uncommon salivary. neoplasm of the head and neck. These lesions often progress insidiously, and they have a propensity for early perineural spread and bony invasion. Distant metastasis to the lungs is fairly common and is usually fatal. We report a rare case of adenoid cystic carcinoma in a patient who on initial evaluation had widespread bony metastasis but no pulmonary involvement.

Introduction

Adenoid cystic carcinomas of the minor salivary glands occur infrequently. These lesions are for the most part asymptomatic, and therefore patients often present when their tumor is at an advanced stage. In this article, we report an unusual case of sinonasal adenoid cystic carcinoma that was characterized by widespread distant bony metastasis and impending spinal cord compression, but no pulmonary involvement.

Case report

A 37-year-old white man was transferred to our institution for palliative radiation therapy for metastatic cancer that involved the lower vertebrae and threatened to compress the spinal cord. He reported a 1-month history of increasing lower back pain and a 20-lb weight loss.

The patient's most recent hospital admission was for treatment of an acute exacerbation of lower back pain and left lower-extremity paresthesia 1 month earlier. At that time, his serum calcium level was elevated at 11.9 mg/dl (range of normal: 8.0 to 9.5), and a metastatic work-up was initiated. Magnetic resonance imaging (MRI) detected multiple lesions involving the lower spinal column and acetabulum (figure 1). A whole-body MRI detected multiple lesions involving the lower thoracic and lumbar vertebrae, the left 8th rib, right 10th rib, right femur, left acetabulum and lilac wing, left lace, and calvaria. Abdominal computed tomography (CT) showed multiple hepatic lesions; chest CT was negative. A biopsy of the right hip lesion was suspicious for a high-grade biphasic epithelioid malignancy (as opposed to a metastatic synovial sarcoma).

[FIGURE 1 OMITTED]

Further evaluation at our medical center revealed that the patient had a left palatal mass, and the otolaryngology service was consulted. At the time of consultation, the patient complained that his left upper incisor was loose; he denied symptoms of nasal obstruction or epistaxis. Examination revealed the presence of a firm, 1.5 x 3-cm lesion that involved the left hard palate, an overlying telangiectasia, and a 0.5-cm area of ulceration (figure 2). Nasal examination revealed narrowing of the left nasal passage, Assessment of the neck was negative for any lymphadenopathy.

[FIGURE 2 OMITTED]

Paranasal CT revealed the presence of a 5.6 x 3.5-cm left maxillary lesion that protruded through the anterior palate as well as widespread soft-tissue and bony destruction (figure 3). Findings on subsequent transpalatal biopsy were consistent with adenoid cystic carcinoma (figure 4). The tumor grade could not be determined because of the limited size of the biopsy sample. When the metastatic acetabular biopsy sample was compared with the palatal biopsy, findings were consistent with a metastasis from a primary salivary tumor.

[FIGURES 3-4 OMITTED]

The patient subsequently underwent palliative radiation therapy to his lower spine along with adjunctive doxorubicin chemotherapy. The patient was discharged after his neurologic condition stabilized, and he did not return for ENT follow-up.

Discussion

Adenoid cystic carcinomas of the major and minor salivary glands are relatively uncommon. They account for 10 to 15% of all salivary malignancies; as many as 60% have been reported to involve the minor salivary glands. (1) The most common sites of minor salivary gland adenoid cystic carcinoma are the soft palate/oral cavity and the sinonasal tract.

Adenoid cystic carcinomas are generally indolent, asymptomatic masses that have a propensity for early perineural extension and bony invasion. The presence of widespread disease and distant metastasis is not uncommon on initial evaluation. Most sinonasal adenoid cystic carcinomas arise in the maxillary antrum, and affected patients usually present late with extensive destruction of neighboring soft tissue and bone. (2) The potential for extensive involvement of vital structures, such as the orbit and skull base, and the relative surgical inaccessibility contribute to a poor prognosis.

Distant metastases are more common than lymph node involvement. As many as 90% of all distant metastases involve the lung. (3,4) The next most common site is the liver. To our knowledge, the widespread bony metastasis without pulmonary involvement seen in our patient is extremely rare.

Adenoid cystic carcinomas are classified into three grades based on their cellular pattern: cribriform and tubular areas without a solid component (grade I), pure or mixed cribriform areas with less than a 30% solid component (grade II), and areas of more than 30% solid component (grade III). Grade III tumor's are generally more aggressive and are associated with a poorer prognosis; low- to high-grade transformation and dedifferentiation have been documented. (5) Nevertheless, tumor grade alone is not predictive of survival, local recurrence, or distant spread. (6)

Our case is a unique example of the aggressive nature of adenoid cystic carcinoma. Because many patients with this cancer ultimately die as a result of distant metastasis, it is not clear that earlier treatment of our patient would have changed the outcome. The unique pattern of spread and the constellation of complaints and findings that characterized this case should be kept in mind by otolaryngologists when managing patients with adenoid cystic carcinoma.

References

(1.) Perzin KH, Gullane P, Clairmont AC. Adenoid cystic carcinomas arising in salivary glands: A correlation of histologic features and clinical course. Cancer 1978;42:265-82.

(2.) Kim GE, Park HC, Keum KC, et al. Adenoid cystic carcinoma of the maxillary antrum. Am J Otolaryngol 1999;20:77-84.

(3.) Spiro RH. Distant metastasis in adenoid cystic carcinoma of salivary origin. Am J Surg 1997;174:495-8.

(4.) Sur RK, Donde B, Levin V, et al. Adenoid cystic carcinoma of the salivary glands: A review of 10 years. Laryngoscope 1997;107: 1276-80.

(5.) Cheuk W, Chan JK, Ngan RK. Dedifferentiation in adenoid cystic carcinoma of the salivary gland: An uncommon complication associated with an accelerated clinical course. Am J Surg Pathol 1999;23:465-72.

(6.) Fordice J, Kershaw C, El-Naggar A, Goepfert H. Adenoid cystic carcinoma of the head and neck: Predictors of morbidity and mortality. Arch Otolaryngol Head Neck Surg 1999:125:149-52.

From the Division of Otolaryngology, Department of Surgery (Dr. Lee and Dr. Stack) and the Department of Anatomic Pathology (Dr. Kapadia), Milton S. Hershey Medical Center, Pennsylvania State University College of Medicine, Hershey.

Reprint requests: Brendan C. Stack, Jr., MD, Associate Professor, Division of Otolaryngology, Pennsylvania State University College of Medicine, 500 University Dr., MCH091, Hershey. PA 17033. Phone: (717) 531-6511; fax: (717) 531-6160; e-mail: bstack@psu.edu

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