Information on the skin biopsy

Selecting the biopsy technique

The contingent relation between biopsy size and differential clinical diagnosis

The choice of biopsy technique is also dependent on differential clinical diagnosis. If these tumours cover the same set of cells and differentiation of sets of cells, histopathological diagnosis becomes difficult, and the dermatopathologist requires more material in order to be able to record all the criteria for differential diagnostics. Demarcating flat melanocytary Naevi of malign melanomas can be histopathologically so difficult that small pigment-cell tumours must always be removed in their entirety. To distinguish melanoma from pigmented basal-cell carcinoma, a partial biopsy will suffice. To distinguish a tough basal-cell carcinoma from a sebacious-gland hyperplasia requires only a superficial shave biopsy, whereas demarcating a tough basal-cell carcinoma from a tricho-blastoma demands a large spindle biopsy. In some cases, an extension into the depths is even the most vital criterion in distinguishing benign from malign neoplasias, for example between syringoma and micro-cystic Adnexa carcinoma.(12) For these reasons, if the complete excision of a malign tumour does not appear to be sensible in the absence of any previous confirmation of the diagnosis, at least a partial biopsy should be carried out; where there are tuberous changes with unclear differential diagnosis, this is generally in the form of a profound biopsy with the scalpel.(2)

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