Rediagnosing one of Smith's patients (John McCann) with "neuromas tumours" (1849).

In 1849, the Irish Professor of Surgery, Sir Robert William Smith, by publishing his "Treatise on the Pathology, Diagnosis and Treatment of Neuroma", collected six previous examples of "general development of neuromatous tumours" and reported three further cases (two personal and one referred) of what is nowadays known as neurofibromatosis. Among these latter cases, there was a 35-year-old cattle-driver, John McCann, who was first admitted at hospital in 1840 because of a large tumour on the right side of his neck thought to be malignant (and a second tumour sublingually) but not operated. McCann was readmitted in 1843 ("in an emaciated state"), because of an immense tumour in his thigh dying few months later "with hepatic symptoms". Smith's post-mortem examination revealed dozens of smaller additional tumours. Based on application of modern diagnostic criteria (to McCann's portrait at second referral) and on pathological grounds (reconsideration of the histopathological report of McCann's neuroma of the thigh), we tentatively hypothesise that this patient could be the earliest (illustrated) example of either: (1) a malignant peripheral nerve sheath tumour (MPNST); (2) neurofibromatosis type 2 (NF2); or (3) schwannomatosis (SWNTS). The progressively enlarging masses, the emaciated state and the later death are in favour of a MPNST (against is the lack of malignant appearance at histopathology); the clinical (and gross pathological) appearance of the tumours as large, rounded, encapsulated, eccentric lesions deflecting the parent nerve over the surface of the tumour is typical of schwannomas (thus, in favour of NF2 or SWTNS). Whatever diagnosis we could consider these tumours could be secondary to a (local) mosaic loss of heterozygosity and ultimately represent type 2 segmental manifestations superimposed on an ordinary autosomal dominant trait (i.e., NF1, NF2 or SWTNS).