Background: Proteus Syndrome is a rare, sporadic overgrowth disorder for which the underlying genetic defect remains unknown. Although the clinical course is well-described, there is no systematic histopathological description of the lesional pathology.

Objective: To describe the histopathological features encountered in a series of patients with Proteus syndrome from a single centre.

Patients/Methods: Patients with Proteus syndrome who had undergone therapeutic surgical resection or biopsy were identified from a database and the histopathological findings were reviewed, with particular reference to descriptive features of the underlying tissue abnormality.

Results: There were 18 surgical specimens from nine patients, median age 4 (range 1–9) years, including four main categories; soft tissue swellings (lipomatous lesions), vascular anomalies (vascular malformation and haeman-gioma), macrodactyly (hamartomatous overgrowth) and others (sebaceous naevus and non-specific features). In all cases the clinical features of overgrowth were due to increased amounts of disorganised tissue, indicating a hamartomatous-type defect in which normal tissue constituents were present but with an abnormal distribution and architecture. Vascular malformations represented a prominent category of lesions, accounting for 50% of the specimens, predominantly comprising lymphatic and lymphovascular malformations. No malignancy or cytological atypia was identified in any case.

Conclusions: The histopathological features of lesions resected from children with Proteus syndrome predominantly include hamartomatous mixed connective tissue lesions, benign neoplasms such as lipomata and lymphatic-rich vascular malformations.

We used calcium-phosphate cement combined with minimal internal fixation to treat 49 fractures of the lateral tibial plateau. There were 25 split depression fractures, 22 pure depression fractures and two bicondylar fractures. Anatomical reduction was obtained in 38 fractures, satisfactory reduction in nine and imperfect reduction in two. Of 44 patients reviewed at one year, 33 were rated as having an excellent reduction. Functional outcome as measured by the Rasmussen score was good or excellent at six months in 92% (44/48) of patients and in 95% (42/44) at one year. Eight (16%) showed some loss of reduction of the plateau. In seven of these the loss of reduction was slight (< 3 mm) and no action was taken. One patient with a deep infection had gross loss of reduction and a poor functional outcome. Calcium-phosphate cement is a useful alternative to bone grafting for the treatment of fractures of the tibial plateau.