## 4 Discussion  
NMSC diagnosis is initially clinical, with histological confirmation following excision. The final diagnosis is always after the pathological examination, although the clinical aspect can suggest the tumor type. The'stretch test' improves diagnostic accuracy in BCC. Dermatoscopy improves the accuracy of initial diagnostics in all NMSC and is helpful in determining the BCC sub-type. Pre-excisional tissue diagnosis can be indicative particularly for reconstruction if a graft or flap is required, or in an anatomically complex area such as the nose. This is best achieved by punch, incisional or shave biopsy under local anesthesia. Shave biopsy is to be avoided in possible cutaneous melanoma. exfoliative cytology has a high diagnostic accuracy in NMSC when ulceration is present and guides the case management where surgical biopsy may be difficult, such as in the very elderly. A tissue sample diagnosis is required prior to radiotherapy (RT).  
The nodular type of BCC is the most common form and may have clinical cystic or pigmented variants. Morphoic BCCs are found almost exclusively on the head and neck, especially the nose. Superficial BCCs are found predominantly on the trunk. Basal cell carcinoma has a number of well-described histological subtypes.  
The term 'infiltrative BCC' is used for all high-risk histological variants containing many BCCs of both high- and low-risk subtypes.  
Figure 5: Recurrent squamous cell carcinoma—7 years post-excision.  
Cutaneous squamous cell carcinoma presents as a keratinizing indurated nodular or crusted tumor that may ulcerate, or it may present as an ulcer alone without evidence of keratinization. Nasal vestibule or ear canal localizations are often diagnosed late, with poor prognosis, as it can be misdiagnosed [9].  
After analyzing our data regarding the correspondence between the clinical and the histological diagnoses, we found that the majority of patients sought medical assistance very late; thus, establishing a high evolution time for aggressive malignant tumors (48 cases with over 10 years evolution for BCC and 21 cases with an evolution of over 2 years for CSCC). A higher evolution time leads to local tumor expansion along with ulcerated and infected tumors, therefore, making clinical evaluation difficult. Diagnosis of NMSC is usually clinical. Biopsy (exfoliative cytology) is recommended where the clinical diagnosis is uncertain, or where the histological features may influence the treatment and prior to radiation therapy (G) [9]. Mohs surgery could be a good technique for skin tumors, especially for areas with high risk of recurrence such as the ear, temple, periauricular regions, retroauricular, nasolabial fold, nose, or upper lip. It is known to have the smallest recurrence rate of 3.4% to 7.9% and has the advantage of preserving healthy tissue, which is notably important, considering the aesthetic and functional outcomes; however, due to the technical issues we cannot apply it to our patients [10].  
Tumors that were clinically low risk, were correlated with pathological aspects of superficial, well defined growth patterns with no perineurial, lymphatic or vascular involvement. High risk tumors were poorly defined and associated with depth expansion as well as perineurial, lymphatic and vascular involvement.  
Evaluating the aspects of clinical and pathological correlations and the predictive values of using clinical criteria for diagnosis, we found that using clinical means to detect a NMSC from a benign lesion had a positive predictive value (PPV) of 86%, and a negative predictive value of 76%. Clinically detecting BCC from other NMSCs had a PPV of 88%, and SCC from other NMSCs a PPV of 60%.