Prevalence and clinical significance of solitary pulmonary sub-segmental microembolism.

BACKGROUND: Solitary pulmonary microembolism is rarely discussed as a distinct diagnostic entity. The purpose of this investigation was to determine the prevalence and clinical significance of embolism limited to subsegmental branches in a group of patients discharged from hospital on anticoagulants with a diagnosis of pulmonary embolism based on ventilation-perfusion imaging followed by selective angiography. MATERIAL AND METHODS: Of 29 consecutive patients with classic signs of pulmonary embolism at angiography, we identified a subgroup of 5 patients with sub-segmental embolism, which was solitary in all cases. RESULTS: Clinical presentation included chest pain (2/5), shortness of breath (2/5, or hypoxemia (1/5). Chest X-rays were normal (2/5), or showed pulmonary oedema (1/5) or atelectasis with (1/5), or without (1/5) pleural effusion. VQ imaging patterns included small subsegmental mismatch (1/5), one segment mismatch (1/5), single (1/5) or triple (2/5) match. The site and size of the microemboli found at angiography were incompatible with the location and severity of symptoms in 4/5 (80%) patients, and with location and extent of Chest X-ray findings and with VQ patterns in all patients. VQ abnormalities were either either disproportionably larger or were non congruent with the vascular territory compromised by the subsegmental embolus. CONCLUSIONS: Sub-segmental pulmonary micro-emboli were always solitary, and not uncommon, comprising 17% of all patients with pulmonary embolism. The location and size of the emboli were inconsistent with clinical, Chest X-ray and scintigraphic findings, suggesting that isolated microemboli are a serendipitous finding, of no clinical significance.

Scintigraphic probability and angiographic diagnostic certainty in acute pulmonary embolism.

The objectives of this study were to determine if diagnostic certainty on angiography correlates with scintigraphic probability for the diagnosis of pulmonary embolism. From a total of 160 consecutive patients who underwent both nuclear imaging and invasive selective pulmonary angiography, we reviewed the xenon-133 ventilation images in 2 posterior oblique views and the Tc-99m macroaggregated serum albumin perfusion scans and angiograms of 40 patients (15 men, 25 women; average age 57 years) who were discharged from the hospital on anticoagulants with a diagnosis of pulmonary embolism. The angiograms were reviewed and the diagnosis of embolism was considered certain in the presence of an intraluminal filling defect, a trailing embolus, or a branch occlusion equal to or larger than a segmental branch (n=29; 73%), and uncertain when the studies were reinterpreted as either equivocal or negative or in the presence of a single, small subsegmental filling defect of questionable clinical significance. The ventilation-perfusion scans were read as high (n=18; 45%), intermediate (n=10; 25%), or low (n=12; 30%) probability. The proportion of patients with diagnostic certainty on angiography in the high-, intermediate-, and low-probability scintigraphic subgroups was, respectively, 100% (18 of 18), 70% (7 of 10), and 33% (4 of 12) (P=0.004). In patients diagnosed with pulmonary embolism based on selective angiography, a lower probability of pulmonary embolism on ventilation-perfusion scintigraphy correlates with a lesser degree of diagnostic certainty on angiography and a higher incidence of single subsegmental emboli.

Phase I study on sentinel lymph node mapping in colon cancer: a preliminary report.

BACKGROUND AND OBJECTIVES: Lymph node (LN) metastasis is one of the most significant prognostic factor in colorectal cancer. In fact, therapeutic decisions are based on LN status. However, multiple studies have reported on the limitations of the conventional pathological LN examination techniques, and therefore, the actual number of patients with LN positive colorectal cancer is probably underestimated. We assume that lymphatic tumor dissemination follows an orderly sequential route. We report here a simple and harmless coloration technique that was recently elaborated, and that allows us to identify the sentinel LN(s) (SLN) or first relay LNs in colorectal cancer patients. The main endpoint of this clinical trial is the feasibility of the technique. METHODS: Twenty patients treated by surgery for a colic cancer were admitted in this protocol. A subserosal peritumoral injection of lymphazurin 1% was performed 10 min before completing the colic resection. A pathologist immediately examined the specimens, harvested the colored SLN, and examined them by serial cuts (200 microm) with H&E staining, followed by immunohistochemical staining (AE1-AE3 cytokeratin markers), when serial sections were classified as cancer free. RESULTS: The preoperative identification of the SLN was impossible in at least 50 of the cases, however, SLNs were identified by the pathologist in 90% of cases. In two patients (10%) SLN was never identified. The average number of SLN was 3.9. Immunohistochemical analysis of the SLN has potentially changed the initial staging (from Dukes B to Dukes C) for 5 of the 20 patients (25%). On the other hand, there was one patient (5%) with hepatic metastasis from adenocarcinoma for whom SLN pathology was negative for metastasis (skip metastasis). CONCLUSIONS: SLN biopsy is readily feasible with identification of SLN in at least 90% of patients with colorectal cancers. Our results indicate that 45% of patients initially staged as Dukes B had tumor cells identified in their SLN when these were subjected to our protocol. This represented a 25% upgrading rate when our complete study population is considered. However, controversy persist about the clinical significance and metastatic potential of these often very small clusters of tumor cells.