Rheumatology Advance Access originally published online on August 7, 2007
Rheumatology 2007 46(10):1625-1626; doi:10.1093/rheumatology/kem152
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Comment on: parotid gland biopsy compared with labial biopsy in the diagnosis of patients with primary Sjogren's Syndrome: reply
Correspondence to: J. Pijpe. E-mail: j.pijpe{at}kchir.umcg.nl
We would like to thank Dr. Morbini and co-workers for their valuable remarks on our study comparing parotid gland with labial biopsy in Sjögren's syndrome (SS) [1]. Morbini and co-workers addressed an important topic regarding the validity of salivary gland biopsies in the diagnosis of SS. In their well performed study regarding multilevel examination of labial gland biopsy specimens in the diagnosis of SS, they showed that the diagnostic specificity of labial biopsies can by increased by almost 10% when using a cumulative focus score [2]. Multilevel evaluation of a labial gland biopsy may indeed improve the reliability of histological grading in SS, which particularly might be of additional value in potential SS cases with a focus score at the cut-off level. Although the amount of tissue available in a parotid biopsy is usually not a problem for SS diagnostics, as it occasionally may be in labial biopsies from patients with advanced SS, it might be very interesting to evaluate whether multilevel evaluation will also increase the specificity and/or sensitivity of parotid gland biopsies.
The second point that Morbini and co-workers mentioned in their letter is the low incidence of subjective morbidity after a labial biopsy in their cohort of patients. They recorded adverse events with the aid of a questionnaire [2]. This subjective assessment might underestimate the amount of local hypoesthesia after labial biopsy. That was the reason we performed a thorough neurological examination (two-point discrimination test) in order to evaluate the objective morbidity of a labial or parotid biopsy in addition to a subjective evaluation using a questionnaire [1]. In agreement with the study of Morbini and co-workers [2] the evaluation of the adverse effects was done by independent clinicians. Combining a subjective assessment with an objective assessment is essential as it is not unusual that patients do not complain about local paraesthesia, even when objective assessment indicates some degree of disturbed sensibility. Although this discrepancy between objective and subjective results might not be clinically relevant, such information might be crucial for comparative studies. Moreover, we agree that in skilled hands both a labial and a parotid biopsy will result in minimal adverse effects, but we rather often encounter in our daily practice patients with a permanent disturbed sensibility of the lower lip due to a diagnostic labial biopsy taken by less skilled clinicians.
At the end of their letter Morbini and co-workers mentioned that there is a need for large comparative studies in order to find out the best diagnostic tools for histopathological evaluation of SS. Morbini and co-workers have a preference for labial biopsies above parotid biopsies because of the specific surgical experience needed for parotid gland biopsies, while labial salivary gland biopsies may be performed directly by clinicians such as rheumatologists. Although taking a parotid gland biopsy as used by Pijpe et al. [1] is a rather simple out-patient technique for e.g. an oral and maxillofacial surgeon, it is indeed not a procedure that is easy to perform in, for example a department of Rheumatology. However, there are some inherent advantages of a parotid biopsy over a labial biopsy in SS patients that are not mentioned by Morbini and co-workers. A parotid biopsy might be preferred for therapy evaluation as repeated biopsies can be taken from the same parotid gland (in combination with saliva samples from the same gland). As such a parotid gland can be used more easily to monitor disease progression and/or disease activity than a labial salivary gland. A second advantage of a parotid gland biopsy over a labial gland biopsy is the potential of parotid biopsies to early diagnose MALT and non-Hodgkin lymphomas, often already at a stage without clinical manifestation (e.g. no swelling of the parotid gland). Although the clinical significance of early detection of lymphoma located in parotid gland tissue is not yet defined, it is in potency an important advantage of parotid biopsies over labial biopsies as these lymphomas are rarely observed in labial salivary glands.
The authors have declared no conflicts of interest.
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- Pijpe J, Kalk WWI, van der Wal JE, et al. Parotid gland biopsy compared with labial biopsy in the diagnosis of patients with primary Sjögren's syndrome. Rheumatology (2007) 46:335–41.
[Abstract/Free Full Text] - Morbini P, Manzo A, Caporali R, et al. Multilevel examination of minor salivary gland biopsy for Sjögren's syndrome significantly improves diagnostic performance of AECG classification criteria. Arthritis Res Ther (2005) 7:R343–8.[CrossRef][ISI][Medline]
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