7

specific clinical diagnosis (cases 1 and 6) in 𝑛 = 232 (3.5%) of instances. Moreover, the lack of a specific clinical diagnosis combined with the absence of usable histological data (case 6 only) occurred in 𝑛 = 25 (0.4%) of all cases. With the chi-square test the differences in the frequencies between the cases were found statistically significant (𝜒2 = 10212.560, 𝑃 < 0.001). There was also a dependence of the relationship between clinical and histological diagnosis with the site of biopsy (𝜒2 = 378.979, 𝑃 < 0.001), By interpreting the adjusted residuals, it was found that the correlation lied mostly between case 3 (as described in Table 1) and the biopsy site of the posterior tegument. Also between case 2 and the head and neck region, as well as case 7 and biopsies taken from the pelvis. Also the biopsies from head and neck and the anterolateral and posterior tegument showed a higher consistency between clinical and histological diagnosis. In Table 1, cases 5 to 7 summarize 𝑛 = 754 skin biopsies with no specific histological diagnosis. Possible reasons that resulted in this difficulty were extrapolated after reviewing the histopathology report forms and classifying the dermatopathologists’ comments. Out of a total of 754 biopsies, 𝑛 = 91 (12.1%) specimens were considered as destructed or inappropriate for microscopic examination and 𝑛 = 39 (5.2%) were found of inadequate quantity, where in 𝑛 = 27 (3.6%) the site of biopsy was regarded as not representative or adjacent to the examined lesion, in 𝑛 = 24 (3.2%) the pathological features were altered due to previous treatment, in 𝑛 = 23 (3.1%) optical microscopy with standard staining was considered as inappropriate for a specific diagnosis, and in 𝑛 = 16 (2.1%) the examined lesion was identified as either 4 Dermatology Research and Practice not fully developed or resolved. The remaining 534 (70.8%) cases were documented as not pathognomonic and without exhibiting distinctive features. 4. Discussion There are many occasions in which a clinician is challenged by a strenuous diagnostic problem. Skin biopsy constitutes a simple and inexpensive procedure performed in the dermatology setting which facilitates clinical decisions regarding diagnosis and treatment. Also, various studies consider histological confirmation as the standard for the correct diagnosis in dermatology as compared to the clinical evaluation, and the results produced in such manner are used in determining the epidemiological characteristics and patterns of skin diseases [1, 2]. Therefore, high diagnostic accuracy is pursued which relies upon the minimization of factors such as inappropriate choice of the lesion, poorly executed technique, unspecified clinical diagnosis and insufficient clinical information, faulty tissue fixation and processing, improper staining for specific diagnoses, or inadequate cooperation between the dermatologist and the dermatopathologist [3– 5]. Furthermore, the diagnostic accuracy can be enhanced by using dermoscopy when selecting the site of biopsy [6] and additionally applying immunohistochemical staining and immunofluorescence techniques when appropriate [7, 8]. A few studies have been conducted in order to assess the diagnostic accuracy of skin diseases by physicians by comparing the clinical to the histological diagnosis. One of these studies measured the diagnostic yield of nondermatologists between 34% to 45% and that of dermatologists being 71% and 75% for inflammatory dermatoses or neoplasms and cysts, respectively [9]. Another study found 76.8% of pathological diagnoses to be consistent with the ones given by the dermatologists [10], whereas a third one measured a clinicopathological agreement of up to 92% with this success being attributed by the author to the close cooperation between the dermatologist and the pathologist [2]. In the present study, which was the largest of this kind to our knowledge, a 68% consistency of clinical and histological diagnoses was observed which is lesser than but in accord with the published data. Moreover, further data produced by this study comprise that a specific histological diagnosis was provided in 83.3% of all cases and usable information for the dermatologists was offered in 97.2% of all