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This is the long awaited second edition of this volume in the WHO international histological classification of tumours series. With the exception of Dr Sobin, only two of the participants in the second edition were involved in the preparation of the first and, inevitably, this reviewer turned to the first edition to compare it with the second. The second edition is now in a much more user friendly paperback format and the material has been reorganised in a more logical and simpler way than in the first edition. Furthermore, the index is now at the end of the book rather than halfway through as it was in the 1980 version. Another major improvement in the second edition is the addition of the TNM classification of tumours of the eye and its adnexa. It makes sense to have the TNM classification included along with histological typing of tumours rather than having to refer to the separately published TNM classification of malignant tumours whenever one is reporting. The photomicrographs are also generally of a higher quality than in the 1980 edition.
However, the second edition is not entirely an improvement on its predecessor. I would have to take issue with the claim on the back cover that it “is more extensive and detailed than the previous edition”. It is certainly more extensive with regard to the number of tumours mentioned, but not more detailed, as there are far fewer explanatory notes than in the first edition, and the explanatory notes suffer from a degree of selectivity, the logic for which is not always obvious. Furthermore, the classification suffers from the “overlap syndrome” and descriptions of skin tumours and CNS tumours would be better left to the relevant histological typing volumes. For example, the explanation of glioblastoma multiforme as “anaplastic pleomorphic cells with or without necrosis replace the normal optic tissue” is hardly a helpful description of what is, is in reality, an extremely rare tumour of the optic nerve.
Although the photomicrographs are generally of higher quality, there are in fact fewer (112 v 150) in the second edition and once again they are highly selected for reasons which are not immediately obvious—for example, there are four figures of a phacomatous choristoma of the eyelid including immunocytochemistry but only one of the much commoner and more difficult problem of conjunctival intraepithelial neoplasia. Final gripes about the photographs relate to the absence of arrows to point out subtle features and inconsistencies in some of the figure legends—for example, “undifferentiated sebaceous adenocarcinoma” when, by definition, there must be evidence of sebaceous differentiation in order for the diagnosis of sebaceous carcinoma to made.
All in all, I think the second edition is something of an improvement on the first edition. It is now more user friendly and the addition of the TNM classification is very helpful. However, the book still suffers from the problems which bedevil the whole series of WHO histological classifications—selectivity, “lowest common denominator” classification, and the construction of the classification by a small group of monospecialists. Nevertheless, the book will still be useful as a common language for use in ophthalmic oncology and a way of resolving disputes between pathologists at meetings.