Pheochromocytoma

MRI abdomen of 14 year old male patient came with uncontrolled hypertension with raised urinary catecholamines showing well defined focal soft tissue intensity mass in the left supra renal gland having intensely hyperintense on T2 W image and hypointense on T1W image. Features are consistent with pheochromocytoma.

Pheochromocytomas are rare but treacherous catecholamine-producing tumors, which if missed or not properly treated, will almost invariably prove fatal. Prompt diagnosis is, therefore, essential for effective treatment, usually by surgical resection. The manifestations are diverse and the tumor can mimic a variety of conditions, often resulting in either erroneous diagnoses or a delayed diagnosis. Imaging is very essential for accurate diagnosis.

Pheochromocytomas are extra adrenal (10%), multicentric (10%), bilateral (5%), and malignant (10%)..Size is variable from 1-20 cm.The treatment is surgical excision of tumor, which is curative in all cases. The initial imaging findings in benign and malignant pheochromocytomas are nearly identical. Only the presence of metastasis can clearly define a lesion as malignant. On CT it appears as round or oval discrete mass with homogenous density. Similar findings have been noted in the present case. Central necrosis, calcification and cystic changes may be present in minority of cases. These vascular lesions enhance uniformly after administration of contrast material. MR is also excellent for evaluating intraadrenal pheochromocytoma.On T1, mass has intensity similar to or slightly less than solid organs. OnT2 lesion is hyper intense as result of their long T2 time. Sometimes adrenal metastases also present overlapping imaging findings. Combination of MIBG,CT and MRI scanning is definitive in the diagnosis of pheochromocytoma.

Focal Pyelonephritis

40 year old male patient came to emergency with history of right lumbar pain and fever, USG Doppler of right kidney shows focal hypoechoic area in upper pole with small anechoic area within. CT scan of the same patient showwed focal hypoenhancing lesion in upper pole of right kidney with small non enhancing area within. These features are suggestive of focal pyelonephritis with evolution of abscess.

Acute focal pyelonephritis (AFP) is a variant of pyelonephritis in which single or multiple discrete areas show changes of inflammation. The sonographic appearances of AFP are varied and can be echogenic, echopoor or of mixed echogenicity, but are typically described as being echopoor. CT typically shows focal hypoenhancing areas. Imaging is done mainly to identify the complications like intra renal and peri renal abscess.

Wilms' tumour with IVC and right atrial thrombus

CT scan of 15 year old female shows large mass lesion (arrow head) in the left kidney pushing the aorta and IVC to right side and tumour is extending in to left renal vein (short arrow), IVC and into the right atrium (long arrow).

Vascular extension to the vena cava occurs in 4% of Wilms tumor cases and can reach the right atrium in up to 1%. When this happens the thrombus is usually not adherent to the vessel wall, and there is blood flow around it. Preoperative chemotherapy can cause thrombus regression and even resolution. If the thrombus persists after chemotherapy, surgery will be a challenge. On the other hand, if the thrombus invades the vessel wall, its removal may not be feasible. In this situation cavectomy is a good surgical strategy because it provides complete resection. The prerequisite for cavectomy is the absence of blood flow in the vena cava on preoperative Doppler ultrasonography.

Colon Lipoma

44 year old male presented to gastroenterology clinic complaining loose stools . Upper GI endoscopy was normal. Patient was referred for CT enteroclysis. The images revealed 4X3.5 cm well defined intralumnal fat attenuation lesion seen in the desecnding colon attached to the lateral wall. The findings are consistent with colonic lipoma.

Colon lipoma was described initially by Bauer in 1757. The incidence was estimated to be about 0.26%. colon lipoma constituted 0.3% of the cases treated for colorectal diseases and 1.8% of the cases of benign colorectal tumor during the same period. Elders are more likely to be involved. Most of the lesions were located at the right side of large bowel, accounting for nearly 90% of cases. The majority of colon lipomas presented as single while only 10% of cases were multiple. Most lipomas are submucosal while some are subserosal location. Some are sessile and some pedunculated. CT scan features of lipoma include well defined well capsulated fat attenuation lesion with not much enhancement are diagnostic of lipoma. MR shows hyperintense lesion on T1 and T2 W imagea and loss of signal in fat saturated images. Treatment is mainly by colonoscopic resection if the lesion is pedunculated and surgery if it is sessile.

The Double Posterior Cruciate Ligament (PCL) Sign - Bucket handle tear of medial meniscus.

25 year old young male soccer player presented with a 1 week history of his right knee locking and was not allowed to extend completely as he walked. On physical examination, the left knee appeared minimally swollen but did not feel warm. There was an audible click when the flexed left knee was extended while varus pressure was applied (McMurray test). MRI was performed, Sagittal fat saturated T2 weighted image of the right knee through the intercondylar notch reveals a thin linier fragment of torn meniscus which appears as a low-signal intensity longitudinally oriented band (arrow) lying beneath and parallel to the posterior cruciate ligament (arrow head), creating a double cruciate configuration, referred to as the double posterior cruciate ligament (PCL) sign. The abnormal hyperintensity in keen joint space and supra patellar region is joint effusion. Patient underwent arthroscopic repair of the torn ligament.

The double PCL sign is associated with bucket handle tears of medial meniscus, At MRI this sign relates to the peripheral (bucket) portion of the meniscus and the displaced inner fragment (handle) portion. Identifying the bucket-handle tears early is critical because, depending on how peripheral and complex the tear is, any delay can compromise the chances for repair. If the tear is not reduced, the meniscal fragment risks further maceration.

Pericardial cyst

A 40-year-old man came for routine health checkup. Chest radiograph was found to be abnormal. He said he had no symptoms, and the results of a physical examination were normal. The chest radiograph (Fig 01) showed a smoothly marginated density in the region of the left cardiophrenic angle that partially obscured the left border of the heart and left dome of diaphragm. A computed tomographic scan (Fig 02) showed a homogeneous and smooth fluid attenuation lesion abutting the left ventricle. No septations or calcifications. The heart and great vessels were otherwise normal, and there was no adenopathy. Coronal and sagittal reformated images (fig03) depict the lesion better. The findings are consistent with pericardial cyst.

Pericardial cysts are an uncommon benign congenital anomaly in the middle mediastinum. They represent 6% of mediastinal masses, and 33% of mediastinal cysts. Other cysts in the mediastinum are bronchogenic – 34%, enteric – 12%, thymic and others – 21%. In the middle mediastinum 61% of presenting masses are cysts. Pericardial and bronchogenic cysts share the second most common etiology after lymphomas.

On CT scan pericardial cysts are thin-walled, sharply defined, oval homogeneous masses . Their attenuation is slightly higher than water density 30 to 40 HU. They fail to enhance with intravenous contrast. USG shows hypoechoic lesion with no calcification or septations. MRI is diagnostic, they appear hypointense on T1 and Hyperintense on T2 W images. They will not enhance on contrast study.

Pulmonary alveolar proteinosis (PAP)

HRCT of 30 year old female shows welldefined ground glass opacities which is associated with marked intelobular septal thickening and a sharp nonanatomic demarcation between normal and abnormal lung suggestive of "Crazy paving" pattern which is typical of PAP.

Pulmonary alveolar proteinosis (PAP) is a rare (1 case per 2 million), diffuse lung disease that is characterized by the alveolar and interstitial accumulation of a periodic acid-Schiff (PAS) stain-positive phospholipoprotein that is derived from surfactant.The lung architecture is otherwise normal, and any associated inflammation or fibrosis is limited in extent. Pulmonary alveolar proteinosis (PAP) occurs in primary and secondary forms. Primary PAP is either idiopathic (90% of cases) or congenital (2% of cases) in origin, whereas secondary PAP occurs in association with various pathologies like hematologic malignancies, particularly chronic myeloid leukemia and lymphomas, occupational exposures and associated with infections. Congenital PAP results from deficiency of surfactant protein B (SP-B) or abnormality of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor β chain.

CT scan with the above findings are almost diagnostic. razy paving is the characteristic finding of PAP on high-resolution CT (HRCT) scanning and consists of patchy, bilateral, geographic areas of ground-glass opacity that are associated with interlobular septal thickening. The disease is often distributed uniformly from the lung apex to the base. Interlobular septal thickening may be encountered more frequently in the lower lung zones.Classically, the abnormal pulmonary parenchyma is demarcated sharply from normal lung areas without a discernible anatomic boundary.

The crazy paving pattern also seen in many other condition like hydrostatic pulmonary edema, diffuse alveolar damage from any number of causes, pulmonary hemorrhage, diffuse pulmonary infections (including M tuberculosis, M pneumoniae, and other bacterial pneumonias), the diffuse form of bronchioloalveolar carcinoma, ARDS, drug-induced pneumonitis, radiation pneumonitis, bronchiolitis obliterans organizing pneumonia, chronic eosinophilic pneumonia, obstructive pneumonitis, acute interstitial pneumonia, and lipoid pneumonia.

Cholesterol gallstones

Fig1: CT scan of 57 year old female shows multiple hypodense small lesions of fatty attenuation seen in the gall bladder suggestive of cholesterol gall stones. Fig 2: USG of gall bladder shows multiple calculi in the GB.

Gall stones are of two types: 1. Cholesterol stones and 2. Pigment stones.

Cholesterol stones are made primarily of cholesterol of 70-80%. Where as pigment stones contain only 20% of cholesterol. Ultrasound is the most sensitive and best investigation for the diagnosis of cholelithiasis. CT can pick up calcified gall stones and cholesterol stone which contain more amount of cholesterol. Cholesterol stones appear dark on the background of isoense bile on CT. CT can miss gallstones which are not calcified.

Hydatid cyst of Liver

Multiphasic study of 55 year old male patient non contrast image shows well defined fluid attenuating lesion seen in the segment 8 of liver with rim calcification. The lesion does not show enhancement on arterial and venous phase. The findings are consistent with calcified hydatid cyst. (Type 5).

The liver is the commonest organ to be involved by the hydatid disease. The hydatid cyst can attain very large size before causing symptoms or may be incidentally dectedted early on investigation.

Types of hydatid cyst accodring to Gjarbi's classification bases on uSG appearance:

Type 1 : Pure fluid collection.

Type 2 : Fluid collection with a split wall.

Type 3 : Fluid collection with daughter cysts.

Type 4 : Heterogenous echopattern.

Type 5: Completely calcified lesion.

Preffered management is combination of Albendazone and PAIR techniqe - Puncture, Aspiration, Injection and Re-aspiration (PAIR).

Pracedure : Percutaneous drainage is performed under aseptic conditions with continuous sonographic guidance and intensive monitoring to treat any complications. Using a transhepatic approach, the cyst punctured by a 20-gauge needle and cyst contents aspirated rapidly. After aspiration, the cyst should be filled with a near-equal volume of 95% ethanol which will be left in the cavity for 20 min. Finally the cyst is reaspirated, irrigated and left partially filled with sterile 0.9% saline. Before and after injection of 95% ethanol, cyst fluid should be sent immediately for cytological and microbiological examination. Staining with neutral red is indicated in a viable cyst, while staining with methylene blue and eosin indicated in a non-viable cyst. Percutaneous drainage will be successful if the endocyst separated from the pericyst and if the reaspirated fluid shows a non-viable cyst. If not, percutaneous drainage was repeated at the same sitting to obtain success. After percutaneous drainage had been performed, all patients should be given albendazole 10 mg/kg body weight for 6 weeks. Othre treatment option is surgery which includes morbidity and mortality.

Hydatid cyst of neck

54 year old female came with neck swelling on the left side. CT scan showing flid attenuation lesion inthe left side of the neck extending to superior mediastinum (arrow). The lesion shows cyst in cyst appearance (arrow head) suggetive of daughter cyst. The findings are consistent with hydatid cyst.

Hydatid cysts in the neck are quite rare, even in areas where the disease is endemic. The role of radiological investigation is important and, in these cases, the involvement of other organs should be investigated. The cyst should be excised as a whole, without being ruptured, to prevent any treatment complications.

Carcinoma of urinary bladder

CT scan of 44 year old male came with history of hematuria showing large intraluminal mass lesion arising form the left lateral wall of the urinary bladder. Biopsy proved to be adenocarcinoma bladder.
CT of another patient with hematuria showing large heterogeneously enhancing soft tissue mass lesion arising from the right lateral wall of urinary bladder. Biopsy proved to be carcinoma urinary bladder.

Bladder cancer is the second most common malignancy of the genitourinary system. Adenocarcinoma of bladder is rare tumors of bladder, accounts to 2%. Majority of tumors are transitional cell carcinomas (90%) and Squamous cell carcinoma (5%). Classic clinical presentation is painless, gross hematuria. Risk factors include smoking, pelvic irradiation, exposure to aniline dyes and chemotherapy with cyclophosphamide. Very often the newely diagnosed carcinoma will be superficial (72%). 5 % come with metastases to lymphnodes, liver, lung, bone and brain. CT and MRI are indicated mainly for staging of the tumor. Superficial bladder cancer has good prognosis with 5-year survival rates of 82-100%. Prognosis for metastatic transitional cell cancer is much poorer with only 5% of patients living 2 years after diagnosis.

Carcinoma cervix with pyometra

CT scan of 52 year old female shows illdefined enhancing soft tissue lesion ( white arrow) in the region of cevix more on the right side with para metrial extnesion. The section through the body of uterus shows collection within the endometrial cavity. The findings are consistent with the carcinoma cervix with pyometra.

Invasive cervical cancer is the third most common gynecologic malignancy. The prognosis is based on the stage, size, and histologic grade of the primary tumor and the status of the lymph nodes. Assessment of the stage of disease is important in determining whether the patient may benefit from surgery or will receive radiation therapy. The official clinical staging system of the International Federation of Gynecology and Obstetrics has led to errors of 65%–90% in stage III and IV disease; the result has been unofficial extended staging with cross-sectional imaging modalities such as computed tomography (CT) and MRI. CT and MRI are useful in staging advanced disease and in monitoring patients for recurrence. The primary tumor is heterogeneous and hypoattenuating relative to normal stroma on contrast material–enhanced scans. Obliteration of the periureteral fat plane and a soft-tissue mass are the most reliable signs of parametrial extension. Less than 3 mm separation of the tumor from the pelvic muscles and vascular encasement are signs of pelvic side wall invasion. Lymphatic spread is along the external and internal iliac nodal chains and the presacral route to the paraaortic nodes. Distant metastases are seen with primary or recurrent disease and can involve the liver, lung, and bone.