Multiple intraparenchymal parotid calculi: a case report and review of the literature.

Abstract

We describe an unusual case of bilateral intraparenchymal parotid stones with unilateral parotitis in a 17-year-old boy. The patient went on to develop multiple parotid abscesses, which we treated with a superficial parotidectomy. To our knowledge, this is only tire second report of intraparenchymal parotid stones in a pediatric patient.

Introduction

Sialolithiasis is a relatively common entity; postmortem studies indicate that the incidence among the general population is 1.2%. (1) Most (80 to 90%) of these calculi are found in the submandibular gland, and the remainder occur in the parotid. Calculi are usually found in the ductal system, where they arise as a result of salivary stasis or slow clearance.

In this article, we report a case of intraparotid calculi that was complicated by abscess formation in a pediatric patient. To our knowledge, this is only the second report of intraparenchymal parotid stones in a pediatric patient.

Case report

An otherwise healthy 17-year-old boy was referred to our outpatient pediatric otolaryngology clinic for evaluation of progressive right-sided parotid swelling and pain over a 3-day period. His pediatrician had started him on cephalexin and obtained contrast-enhanced computed tomography (CT) of the face, which revealed multiple parotid calcifications bilaterally. The patient' s medical and surgical history were unremarkable, and he was not taking any other prescription medications or vitamin supplements. He had no risk factors for human immunodeficiency virus infection.

On physical examination, the patient's temperature was 96.4[degrees]F (tympanic), and he appeared to be healthy and in no acute distress. Examination of his face revealed a tender right parotid gland without swelling or fluctuance. No purulent material could be expressed from Stensen's duct. His facial nerve function was grossly intact. Findings on the remainder of the examination were unremarkable. His serum calcium, phosphorus, and uric acid levels were normal. SSA and SSB antibodies were nonreactive. We recommended continuation of antibiotics and planned to allow the infection and inflammation to resolve with medical treatment. If symptoms persisted or recurred, we intended to proceed with a superficial parotidectomy.

The patient's symptoms did progress, and he returned 3 days later with an exquisitely tender, fluctuant area over his right parotid gland (figure 1). He had moderate trismus, but his facial nerve function remained normal. Repeat CT revealed multiple abscesses in the right parotid gland (figure 2). Because of the extensive number of abscesses, we performed a superficial parotidectomy with facial nerve monitoring. Intraoperatively, the multiple abscesses were drained; the largest was approximately 3 to 4 cm and it had bored through the superficial lobe and into the deep lobe.

[FIGURE 1-2 OMITTED]

The purulent fluid was sent to the Centers for Disease Control and Prevention (CDC) for aerobic, anaerobic, fungal, and acid-fast bacilli staining and culture. Several months later, the CDC notified us that it had isolated Hemophilus aphrophilus. Histologic examination of the parotid tissue identified multiple intraparenchymal calcified cystic structures (figure 3).

[FIGURE 3 OMITTED]

Postoperatively, the patient remained in the hospital for 2 additional days while receiving broad-spectrum antibiotics. He was discharged home on amoxicillin/clavulanic acid. At the 1-week follow-up, he was feeling well, his facial nerve function was normal, and the incision was healing appropriately. At the 4-month follow-up, he exhibited no abnormality of the contralateral gland.

Discussion

Calculi are unusual sequelae of inflammation of the salivary gland. They develop as a result of debris mineralization, but their exact etiology remains unknown. Burnstein et al performed x-ray diffraction and chemical analyses of six parotid gland stones and found that the three major crystalline components were apatite, magnesium-substituted whitlockite, and octacalcium phosphate. (2)

Although parotid stones can form at any age, they are rare in children for reasons that are not fully understood. Two hypotheses have been proposed. One is that children have a lower salivary calcium concentration than do adults, (3) and the other is that children have a higher rate of salivary flow than do adults. (4)

The two most common bacterial pathogens found in sialadenitis are Staphylococcus aureus and Streptococcus viridans. In our patient, however, the cultured organism was H aphrophilus. This organism is part of the normal oral flora, but it does become virulent on rare occasions. It is most commonly associated with a group of gram-negative bacilli collectively known as HACEK (for Hemophilus parainfluenzae, H aphrophilus, Hemophilus paraphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae). Together, these bacilli account for approximately 5 to 10% of all cases of infective endocarditis.

There have also been reports that H aphrophilus has been cultured from brain abscess collections and osteomyelitis specimens (5-8) Parotid duct sialolithiasis has been reported in the pediatric medical literature on several occasions. (9-11) Seifert et al reviewed 1,200 cases of major salivary gland calculi in 1986 and noted that the parotid was involved in fewer than 10% of cases, and the ratio of parenchymal to ductal occurrences was 1:35. (12) In 1979, Fesharaki et al published the first case report of a pediatric patient (a girl) with intraparenchymal parotid calculi. (13) Her surgical specimen contained seven calculi within the gland parenchyma.

There are no effective pharmacologic options available to dissolve salivary calculi. Dilation of salivary ducts is usually employed to retrieve stones that are small and distally located. For large or more proximally located stones, sialoadenectomy or surgical extirpation of the gland is usually performed. Both of these procedures carry inherent risks of bleeding, infection, Frey's syndrome, and facial nerve injury, but these risks are small.

Ultrasound-guided piezoelectric extracorporeal shockwave lithotripsy (ESWL) has been used in Europe to evaluate and treat salivary gland calculi. (14,15) Kulkens et al performed ESWL on 42 patients with parotid calculi and found that 5 of 10 patients who had intraparenchymal parotid calculi were free of stones after treatment. (14) The mean follow-up period for all patients in their study was 63 months (range: 7 to 96). In general, stones that were smaller than 1.0 cm in diameter responded better to ESWL than did larger stones. But because ESWL is no readily available in the United States at this time, superficial parotidectomy remains the gold standard for complicated sialolithiasis.

References

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(2.) Burnstein LS. Boskey AL, Tannenbaum PJ, et al. The crystal chemistry of submandibular and parotid salivary gland stones J Oral Pathol 1979:8:284-91.

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(10.) Bodner L, Fliss DM. Parotid and submandibular calculi in children. Int J Pediatr Otorhinolaryngol 1995;31:35-42.

(11.) Kaufman S. Parotid sialolithiasis in a child. Am J Dis Child 1968 115:623-4.

(12.) Seifert G, Miehlke A, Haubrich J, Chilia R. Diseases of the Salivary Glands: Pathology, Diagnosis, Treatment, Facial Nerve Surgery. Stuttgart: Georg Thieme Verlag, 1986:85-90.

(13.) Fesharaki R, Baloochy M, Sonbolastan M, Fotuhi A. Parotid gland calculus: Report of a case. J Laryngol Otol 1979;93:737-9.

(14.) Kulkens C, Quetz JU, Lippert BM, et al. Ultrasound-guided piezoelectric extracorporeal shock wave lithotripsy of parotid gland calculi. J Clin Ultrasound 2001;29:389-94.

(15.) Ottaviani F, Capaccio P, Rivolta R, et al. Salivary gland stones US evaluation in shock wave lithotripsy. Radiology 1997;204 437-41.

From the Division of Otolaryngology--Head and Neck Surgery, Department of Surgery, University of Alabama at Birmingham School of Medicine (Dr. Lindman), and the Department of Pediatric Otolaryngology, Children's Hospital of Alabama, Birmingham (Dr. Woolley).

Reprint requests: Jonathan P. Lindman, MD, HAS2, 1501 5th Ave. S., Birmingham. AL 35212-6889. Phone: [phone]; fax: [phone]; e-mail: [e-mail]