Pseudoaneurysms complicating organ transplantation: roles of CT, duplex sonography, and angiography

In a retrospective study of proved pseudoaneurysms (PAs) in 15 patients with transplanted organs (11 liver, three kidney, one pancreas), the results of computed tomography (CT), duplex sonography, and angiography were reviewed. Of the 15 cases of PA, eight occurred at the arterial anastomosis and seven were nonanastomotic. Three of the eight anastomotic PAs were caused by infection. Of the seven nonanastomotic PAs, four were caused by percutaneous biopsy, two were caused by infection, and one was of undetermined cause. In nine (60%) of the 15 patients the PAs were incidentally detected at imaging studies performed for other reasons. Diagnosis requires a high degree of suspicion. CT was performed in nine cases and duplex sonography in ten. The diagnosis of PA was made with CT in six (67%) patients and with duplex sonography in five (50%). CT and duplex sonography could not enable diagnosis when the PA was small, when the arterial anastomosis was not included in the field of study, or when enhancement with intravenously administered contract material was suboptimal. Angiography depicted the PAs in all 15 patients. In three liver transplant recipients with gastrointestinal tract bleeding, the causative PAs were detected only with angiography.     

Spacing of cytochrome oxidase blobs in visual cortex of normal and strabismic monkeys

Some models of visual cortical development are based on the assumption that the tangential organization of V1 is not determined prior to visual experience. In these models, correlated binocular activity is a key element in the formation of visual cortical columns, and when the degree of interocular correlation is reduced the models predict an increase in column spacing. To examine this prediction we measured the spacing of columns, as defined by cytochrome oxidase (CO) blobs, in the visual cortex of monkeys whose binocular vision was either normal or disrupted by a strabismus. The spatial distribution of blobs was examined in seven normal and five strabismic macaques. Tangential sections through the upper layers of the visual cortex were stained to reveal the two-dimensional (2D) pattern of CO blobs. Each blob was localized and their center-to-center spacing, packing arrangement and density were calculated using 2D nearest-neighbor spatial analyses. The mean center-to-center spacing of blobs (590 microm for normally reared and 598 microm for strabismic macaques) and the mean density of blobs (3.67 blobs/mm2 for normally reared and 3.45 blobs/mm2 for strabismic macaques) were not significantly different. In addition, the 2D packing arrangement of the blobs was not affected by strabismus. While it is clear that neural activity plays a key role in the elaboration and refinement of ocular dominance cortical modules, we conclude that it does not determine the spatial period of the pattern of CO blobs. This suggests that aspects of the neural circuitry underlying the columnar architecture of the visual cortex are established prenatally and its fundamental periodicity is not modifiable by experience.      

Parathyroid Neoplasms: The Army Hospital (Research & Referral) Experience

Background

Neoplasms of the parathyroid are common but parathyroid carcinoma is exceptionally rare. In contrast to most other malignant endocrine tumours that are usually less hormonally active, malignant parathyroid tumours are hyper functional. Malignant parathyroid tumours pose a diagnostic dilemma for the pathologist.

Objective

To study the clinicopathological profile of a case series of parathyroid neoplasms and determine features which facilitate a malignant diagnosis.

Methods

A retrospective analysis of seven cases of surgically treated parathyroid tumours over a three-year period at a single centre was done. Clinical, haematological, biochemical, and radiological data was accrued from medical records. The histopathology slides were reviewed along with the clinicopathological profile in an attempt to delineate markers of malignancy.

Results

Patients ranged from 30 to 58 years of age. Males and females were approximately equal. Weakness and bone pain were the commonest presenting symptoms. Over 50% had significant hypercalcaemia and all had elevated serum parathormone. Clinically apparent mass was seen in only one. All tumours were successfully localised using CT scan and MRI. Thick fibrous capsule and broad septal fibrosis was seen in both the carcinomas; these were thin in the adenomas. Mitotic counts of 1-3 per high power field (HPF), capsular invasion and nodal metastasis were noted in the malignant tumours.

Conclusion

Elevated serum calcium and parathormone values point to a parathyroid neoplasm. Current imaging modalities are successful in localising the tumour preoperatively. Markedly elevated serum calcium, broad fibrous bands, mitotic counts and capsular invasion are indicators of malignancy.Key Words: Parathyroid, Adenoma, Carcinoma