Subtyping basal cell carcinoma by clinical diagnosis versus punch biopsy.

International guidelines on the diagnosis and treatment of basal cell carcinoma (BCC) recommend a punch biopsy in the majority of clinically suspected BCC prior to treat ment. This is to confirm diagnosis and to identify the histological subtype (superficial, nodular, aggressive), which is necessary to know for optimal treatment selection (1, 2). A punch biopsy can detect the most aggressive subtype in 84–92% of cases, but has the disadvantages of discomfort for the patient and costs for the health care system (3–5). In contrast, clinical diagnosis is a painless, and possibly money-saving procedure (6). However, the difference in diagnostic accuracy of BCC subtyping between punch biopsy and clinical diagnosis has never been evaluated. This study compares the diagnostic accuracy of clinical assessment and histological diagnosis by punch biopsy for subtyping of BCC. Furthermore, we evaluated the impact of omitting the punch biopsy on treatment recommendations. MATERIALS AND METHODS Eligible patients attending the outpatient department of Dermatology of the Maastricht University Medical Centre (MUMC) and the Erasmus Medical Centre Rotterdam (Erasmus MC), the Netherlands, were included between August 2011 and August 2012. Included were patients aged ≥ 18 years with a clinically suspected primary BCC that was histologically confirmed on surgical excision specimen. Exclusion criteria were: genetic skin cancer syndromes and use of immunosuppressive drugs. All patients gave written informed consent for participation. Clinical diagnosis of the most aggressive BCC subtype was made by one of the dermatologists specialized in oncology (3 at MUMC, 2 at Erasmus MC), based on the criteria of Crow-son (7). A distinction was made between superficial, nodular and aggressive BCC. Subsequently, a 3-mm punch biopsy was obtained from the clinically most aggressive tumour area. Superficial and nodular BCC were surgically excised with a 3-mm margin, aggressive BCC with a 5-mm margin. Incompletely excised BCC were re-excised and Mohs' micrographic surgery was performed in facial high-risk BCC (8). All biopsy and excision specimens were haematoxylin and eosin stained. Biopsies were (partially) cut in serial sections of 150 µm. Four serial sections of 4–5 consecutive slices were made. Excision specimens were cut at 2 mm, completely imbedded and one slice per section was made. Histopathological slides were evaluated by 2 dermatopathologists, who were unaware of the diagnosis of the other pathologist and blinded to the clinical diagnosis. The most aggressive BCC subtype was recorded following histological criteria (7, 9). Aggressive BCC comprised infiltrative/morpheaform, micronodular and basosquamous BCC. This …