Sjögren's syndrome is a chronic inflammatory autoimmune disease. Its clinical characteristics are dry eyes (keratoconjunctivitis sicca) and dry mouth (xerostomia) and its histological characteristic is lymphocytic infiltration and destruction of the salivary and lacrimal glands [1]. Labial minor salivary gland biopsy is used as a part of the diagnostic workup for suspected Sjögren's syndrome. The focus score in minor salivary gland biopsy is one of the revised classification criteria for Sjögren's syndrome proposed by the multicenter European study [2]. Among the techniques used to obtain the labial minor salivary gland, the most widely used method is conventional incisional lip biopsy [3]. This technique, however, is time consuming and requiring surgical instruments and assistance to be performed. The biopsy using a minimal incision with a needle tip of the labial minor salivary gland is a new technique that can easily be done as an office procedure causing minimal discomfort to the patients.

This study is to compare the usefulness and complications of biopsy using a minimal incision with a needle tip with those of conventional incisional lip biopsy in the diagnosis of Sjögren's syndrome.

A retrospective chart review of all patients requested for the minor salivary gland biopsy for the diagnosis of Sjögren's syndrome at the tertiary hospitals from January 2005 to December 2008 was performed. One hundred forty-three patients were enrolled and they were 116 females (81.1%) and 27 males (18.9%).

Patients were divided into two groups depending on the biopsy techniques as the biopsy using a minimal incision with a needle tip and the conventional incisional lip biopsy. The existence and numbers of the minor salivary gland obtained and complications of the two techniques were assessed. The adequacy of the specimen is defined as the existence of at least one salivary gland tissue adequate for the diagnosis. This study protocol was approved by Institutional Review Board of Seoul National University Hospital.

Out of 143 patients, 56 patients underwent the conventional incisional lip biopsy and 87 patients received the biopsy using a minimal incision with a needle tip. In the biopsy using a minimal incision with a needle tip group, adequate salivary gland samples were obtained from 85 patients out of 87 patients (97.7%). In the conventional incisional lip biopsy group, adequate specimens were acquired from 44 patients out of 56 patients (78.6%). The success rate to obtain adequate biopsy specimens was significantly higher in the biopsy using a minimal incision with a needle tip group than in the conventional incisional lip biopsy group (P<0.0001) (Table 1). In the patients with adequate specimens, the numbers of obtained salivary glands were not different among two groups (needle tip biopsy 1.78 vs. incisional lip biopsy 1.43, P=0.111). There was no complication in the patients after the biopsy using a minimal incision with a needle tip. In the conventional incisional lip group, one patient complained transient numbness of the lip.

The biopsy using a minimal incision with a needle tip of the minor salivary gland is a new less invasive technique targeting the gland itself directly. It was easy to perform and safe. In this study, we had a better result with this technique than with the conventional one in term of the adequate specimen in the diagnosis of Sjögren's syndrome.

There is yet no definite or simple diagnostic test for Sjogren's syndrome [4]. According to the European criteria proposed in 1993, diagnosis requires 6 items, which are ocular symptoms, oral symptoms, evidence of keratoconjunctivitis sicca, focal sialadenitis by minor salivary gland involvement, instrumental evidence of salivary gland involvement, and presence of autoantibodies [2]. After that, a new set of classification criteria in a joint effort by the American and European Consensus Group was proposed [5]. The main change is that a positive Ro/La serology and histopathology is compulsory for the diagnosis. A minor salivary gland biopsy with a focus score ≥1 is a positive histopathology for the criteria. A focus is defined as an agglomerate of at least 50 mononuclear cells; the focus score is defined by the number of foci in 4 mm² of glandular tissues [6].

The technique for minor salivary gland biopsy was first introduced in 1966 [7,8]. It made an elliptical incision of oral mucous membrane down to the muscle layer [9]. After that, many modifications in a type or length of incision were reported [3,4,10,11,12,13,14,15,16,17,18,19,20,21,22]. The minor salivary gland punch biopsy was introduced in 2001 [17]. Although many techniques were introduced as substitutions for the conventional incisional lip biopsy, it is still generally used because of not being too difficult to perform and not making significant problems [3].

In this study, we introduced a less invasive biopsy technique with a needle tip. No special equipments but a needle, forceps and gauzes were required for this simple procedure. Complete wound healing can be achieved in 5 days even without the wound closure with sutures. Since this technique is a targeted procedure to the salivary glands, it is helpful to harvest salivary gland tissues selectively without surrounding tissues those are not necessary for the diagnosis. On the contrary, the specimen after the conventional incisional lip biopsy contains surrounding soft tissues those are not necessary for the diagnosis (Fig. 2).

In conclusion, the less invasive labial minor salivary gland biopsy using a minimal incision with a needle tip was easy to perform and safe and showed the better result than the conventional incisional lip biopsy in terms of the adequate specimen in the diagnosis of Sjögren's syndrome. So it might be a good alternative to the conventional incisional lip biopsy.