Monday, June 29, 2009

Intestinal Carcinoid

CT Enteroclysis of 55 year old male came with history of dull aching intermittent pain abdomen with episodes of subacute intestinal obstruction. The axial contrast enhanced CT enteroclysis image shows a well defined brilliantly enhancing focal lesion seen in the right iliac fossa causing significatn luminal narrowing of one of the ileal loop. Rest of the structures of abdomen were unremarkable. The coronal refoamatted image better shows the relation with the iliac vessels.

Histology: Carcinoid tumors are relatively rare neuroendocrine tumors. They constitute approximately 2% of all gastrointestinal tumors. Carcinoid tumors belong to a category of tumors called apudomas (amine precursor uptake and decarboxylation tumors) because they arise from endocrine amine precursor uptake and decarboxylation cells that can be found throughout the gastrointestinal tract and in other organs such as the pancreas and the lung. Microscopically, carcinoid tumors are made up of small round regular cells containing a round nucleus and clear cytoplasm. A prominent nucleolus is often present. he presence of elevated excretion of 5-hydroxyindoleacetic acid (5-HIAA) is suggestive of a functioning carcinoid tumor.
Clinical Presentation : Carcinoid tumors are characteristically slowly growing tumors that may go unrecognized for many years. The symptoms are often vague, such as intermittent abdominal pain. The diagnosis is typically not made until the patient undergoes exploratory surgery. These tumors most commonly occur in the fifth or sixth decade of life. The average time from the onset of symptoms to the diagnosis exceeds 9 years. In many cases the diagnosis is not suspected until the patient develops carcinoid syndrome, which typically does not occur until the disease has spread to the liver. However, only 10% of patients will develop the carcinoid syndrome, which is more common with tumors of the ileum and jejunum but also occurs with bronchial and other carcinoid tumors.
Radiology: Small-bowel carcinoid tumors are neuroendocrine neoplasms that present unique imaging challenges. In their early stages, the tumors are small and confined to the bowel wall. Small-bowel series and enteroclysis may be more sensitive for detection than CT or MRI. As the tumor grows, extension outside the involved bowel loop may occur, with infiltration of the mesentery and desmoplastic reaction, which results in a characteristic appearance on small-bowel contrast examinations and cross-sectional imaging. In patients in whom there is a high clinical suspicion of carcinoid tumor but inconclusive barium studies or CT, angiography can be performed and may show the submucosal mass because of its vascularity.Alternatively, in this situation, CT angiography may also be used to localize the mass on the basis of its vascularity and in many cases may obviate conventional angiography.
In addition to contrast studies and CT, nuclear medicine techniques using indium-111– or iodine-123–labeled octreotide or iodine-131–labeled metaiodobenzylguanidine (MIBG) are helpful for diagnosing and locating carcinoid tumors and identifying their metastases.
Surgery is the mainstay of treatment.

Saturday, June 20, 2009

Confluent Hepatic Fibrosis (CHF)

Multiphase CT scan of 13 year old male patient with known case of cirrhosis, non contrast image showing atrophy of left lobe with capsular retraction. Arterial phase image does not show any enhancement. Venous phase image shows faint wedge shaped enhancement in segment IVa (arrow head) and the delayed image shows progressive incresed and persistant enhancement in segment IVa (arrow). Rest of the liver shows lace like enhancement. No mass effect or vascular displacement. The findings are consistant with Confluent hepatic fibrosis (CHF).

CHF Can be seen on imaging in approximately 14% of patients with advanced cirrhosis who are candidates for liver transplantation. It is associated with volume loss seen as retraction of overlying hepatic capsule or total shrinkage of segment or lobe.

Imaging Findings:
CHF is seen incidentally in patients with advanced cirrhosis who undego pretransplant imaging or imaging to ruleout hepatocellular carcinoma. Best diagnostic clue for CHF is pre-contrast CT showing hypo attenuating lesion with volume loss that becomes isoattenuating or minimally hypoattenuating at post-contrast CT, especially if wedge-shaped, located in medial segment of left lobe &/or anterior segment of right lobe, in patients with advanced cirrhosis. In our case the non contrast images are not showing typical hypoattenuation lesion. Wedge-shaped lesions radiate from porta hepatis & extend tohepatic capsule. Peripheral lesions are remote from porta hepatis. Lobar or segmental involvement, most commonly in lateral segment of left lobe. Retraction of overlying capsule seen in 90% cases.
The lesions are isoattenuating on post contrast images in 80% and hperattenuating on delayed scans. They show delayed persistent enhancement due to variability in contrast enhancement of confluent fibrosis relates to relative vascularity & extent of fibrosis.

MR imaging does show morphological changes & characteristic locations that suggest diagnosis, but no more so than CT. Lesions appear as regions of hypointense signal relative to adjacent liver parenchyma on T1 imaes and hyperintense on T2 due to prominant edema. They show delayed progressive enhancement on administration of gadolinium.
Differential diagnosis for focal liver lesions with capsular retraction apart from CHF are Cholangiocarcinoma, Treated metastases and sclerosing cholangitis.

Thursday, June 11, 2009


21 year old male presented to ENT specialist complaining nasal mass and nasal block. Patient was reffered for CT scan of para nasal sinuses. Fig a and b shows curvilinear calcific density lesion seen in the right nasal cavity between theinferior turbinate and nasal septum. No soft tissue associated with the lesion. The findings suggestive of rhinolith.

Rhinolith is calcareous concretions around calcinated intranasal foreign bodies within the nasal cavity. Patient may not always gives history of foriegn body insertion in to nasal cavity. It is usually found in the anterior part of the nasal cavity and is usually diagnosed on history and clinical examintion. In such a condition, radiological evaluation is needed for differential diagnosis and to detect any related complications. CT scan is useful in a posteriorly situated mass which may cause difficulties in diagnosis.
On CT scan, it appears as a homogenous, high-density lesion with smooth mineralization.The central portion of the lesion, which may contain organic material, may be of a somewhat lower density, or a foreign-body nidus may be seen. The most important differential diagnosis include haemangioma, osteoma, calcified polyps, enchondroma, dermoid, chondrosarcoma, osteosarcoma, syphilis and tuberculosis. The complications reported are sinusitis, septal perforation, palatal perforation, recurrent otitis media, and recurrent dacryocystitis.

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