Hypertrophic Pulmonary Osteoarthropathy (HPOA)

Bone scan image shows diffuse increased uptake along the periosteum/cortical margins of both tibias (arrows), sparing the epiphysis, in this patient with lung cancer.

Facts: HPOA

• Clinical syndrome that includes clubbing of fingers/toes, periostitis of tubular bones of extremities and arthritis
• Originally described in association with pulmonary lesions
• Most commonly associated with pulmonary tumors (10% of cases)
• Patients can be asymptomatic or present with arthralgia, arthritis or bone pain
• Histopathology shows edema, mononuclear infiltrates and later osteoid formation of the periosteum
• Commonly involves long bones of forearms and legs, spared axial skeleton and skull

Imaging

• Symmetric periostitis along bony shafts, confined to diaphysis; do not involve joint
• Regular and undulating periosteal reaction
• On bone scan, there is diffuse increased uptake along the periosteum or cortical margins of long bones with sparing of epiphysis

Disorders Described with HPOA

• Pulmonary: cancer, metastasis, mesothelioma, infection and bronchiectasis
• Mediastinum: thymic cancer, thyroid cancer, esophageal leiomyoma, Hodgkin's disease
• Heart: cyanotic heart disease, bacterial endocarditis
• Others: liver cirrhosis, inflammatory bowel disease

Reference:

Vigorita VJ, Ghelman B, Mintz D. Orthopaedic Pathology, 2nd edition, 2007.

Carotid Cavernous Fistula (CCF)

The author would like to thank Drs Thanwa Sudsang and Tom Osborne for helping with labeling the vessels in these angiographic images.

AP and lateral views of the right carotid artery injection show simultaneous opacification of venous structures (superior/inferior ophthalmic veins, middle cerebral vein) and dilatation of the veins due to the presence of CCF in this patient who had recent head trauma.

Facts: CCF

• Rent in the wall of cavernous carotid artery with fistulous communication to the venous spaces of the cavernous sinus
• Either due to trauma (post-traumatic CCF) or ruptured cavernous carotid artery aneurysm
• Traumatic CCF typically seen in young adult male, post motor vehicle collision
• Non-traumatic CCF seen in elderly, female more common than male
• Clinical: venous hypertension (i.e., proptosis, chemosis, retinal hemorrhage, headache)
• Feared complication: venous hypertension of deep vein system and subsequent venous infarction (this can occur if flow from carotid into the cavernous sinus is diverted into deep venous system)

Urgent Treatment Required If:

• Worsening symptoms: increasing proptosis, diminishing visual acuity, increasing intraocular pressure, elevated intracranial pressure
• Extension of pseudoaneurysm or venous varix, or rupture into subarachnoid space

Treatment: endovascular occlusion of fistula with a detachable balloon device, while preserving flow in the carotid artery. Coil embolization is an alternative possible treatment.

Reference:

Morris P. Practical Neuroangiography, 2nd edition, 2007.

Occupational Radiation Dose Limits

Facts:

• International Commission on Radiological Protection (ICRP) issues periodic recommendations on radiation protection. The Commission was founded in 1928.
• ICRP's latest publication was Publication 103 (2007)
• ICRP effective dose limit for radiation worker (occupational dose limit) = 20 mSv per year when averaged over 5 years; any year limit to 50 mSv
• The most highly exposed workers are unlikely to receive regular annual effective doses more than 5 mSv
• Radiation workers should be monitored using personal dosimeter (film badges, TLDs)
• In emergency situations, occupational exposure can exceed these dose limits if lifesaving actions are involved. Older workers with low lifetime accumulated effective doses should volunteer for emergencies.

Reference:

Huda W. Review of Radiologic Physics, 3rd edition, 2009.

Image Credit: www.thermo.com

Extraadrenal Pheochromocytoma: MRI

Fig. 1: Axial T2-weighted MR image with fat suppression shows a well circumscribed retroperitoneal soft tissue mass below the aortic bifurcation with heterogeneous high T2 signal intensity.
Fig. 2: Post contrast MR image shows heterogeneous enhancement of the mass.

Facts: Extraadrenal Pheochromocytoma

• 10% of all pheochromocytoma
• Most in the abdomen (98%)
• Along prevertebral and paravertebral ganglia, including the organ of Zuckerkandl (which is the only macroscopic extraadrenal sympathetic paraganglia located at the origin of inferior mesenteric artery)
• Benign or malignant difficult to determine by histology. If there is local invasion or metastasis to non-chromaffin tissues --> malignant
• Extraadrenal pheochromocytoma metastasizes more often than adrenal counterpart

MR Imaging Appearance

• High T2 signal intensity, classic "salt-and-pepper" pattern on T2WI
• Enhancing, usually heterogeneous
• No lipid content (lack of signal dropout on opposed-phase images)

Our case - extraadrenal pheochromocytoma below the aortic bifurcation incidentally found on MRI, confirmed with I-123 MIBG and serum catecholamines. It should be noted that half of all pheochromocytomas are now discovered incidentally on imaging.

Reference:

Elsayes KM, Narra VR, Leyendecker JR, et al. MRI of adrenal and extraadrenal pheochromocytoma. AJR 2005;184:860-867.

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Ultrasound Features of Malignant Breast Mass

An ultrasound image shows an irregular solid mass with malignant features including ill-defined border, microlobulations, spiculations (seen as hyperechoic band around the mass), taller than wide and angular margin. This was confirmed to be invasive ductal carcinoma at biopsy.

US Features of Malignant Breast Mass

• Marked hypoechogenicity
• Spiculation: highest positive predictive value for malignancy
• Taller than wide
• Angular margin
• Shadowing
• Microlobulation
• Duct extension
• Calcifications
• Branch pattern

Reference:

Cardenosa G. Breast imaging companion, 2nd edition, 2000.