Embedded ring injury - a rare presentation with an atypical aetiology.

A 45-year-old female patient presented to clinic with an almost completely embedded ring in the volar aspect of her right ring finger, with complete reepithelialisation over the superficial aspect of the ring. We present this unusual case of an embedded ring after an insect bite on the patient's ring finger. The patient had worn the ring for the previous 5 years without removing it and did not report any discomfort or traumatic injury. We discuss this case in the context of previously reported cases of an embedded ring, a rare presentation in itself, highlighting the key differences in both this patient's aetiology and the risk factors associated with the presentation.

Recurrent gluteal haematoma: two internal iliac artery-associated bleeding points.

Isolated iliac artery aneurysms are extremely rare. Gluteal artery aneurysms are also rare, more commonly affecting the superior gluteal artery in association with penetrating trauma, with those of the inferior gluteal artery usually associated with pelvic fractures. We discuss a diagnostically challenging presentation of recurrent subcutaneous gluteal haematoma due to two separate internal iliac artery-associated bleeding points. A 67-year-old man was referred, from a peripheral hospital, with a right-sided subcutaneous gluteal haematoma. This manifested 28 days following minor non-penetrating, non-fracture-associated trauma. Despite repeat blood transfusions, albeit interspersed with days of haemodynamic stability, and despite exclusion of relevant bleeding sources at endoscopy and two surgical explorations, it was only until contrast CT scanning was requested that both bleeding sources were identified and successfully treated by endovascular coil embolization. This provides an important variant and lesson to supplement current literature and understanding of more diagnostically challenging cases of an extremely rare presentation.

Heterozygosity for p53 promotes microsatellite instability and tumorigenesis on a Msh2 deficient background.

In colorectal tumorigenesis, loss of function of the mismatch repair genes is closely associated with genomic instability at the nucleotide level whereas p53 deficiency has been linked with gross chromosomal instability. We have addressed the contribution of these two forms of genetic instability to tumorigenesis using mice mutant for Msh2 and p53. As previously reported, deficiency of both genes leads to rapid lymphomagenesis Here we show that heterozygosity for p53 also markedly reduces survival on an Msh2 null background. We characterized the patterns of genomic instability in a small set of tumours and showed that, as predicted p53 deficiency predisposes to aneuploidy and Msh2 deficiency leads to microsatellite instability (MSI). However, heterozygosity for p53 in the absence of Msh2 resulted in increased MSI and not aneuploidy. This implied role for p53 in modulating MSI was confirmed using a large cohort of primary fibroblast clones. The differences observed were highly significant (P<0.01) in both the fibroblast clones (which all retained p53 functionality) and the tumours, a proportion of which retained p53 functionality. Our results therefore demonstrate a dose sensitive role for p53 in the maintenance of genomic integrity at the nucleotide level.