Miliary Pulmonary Metastasis

Axial CT image shows multiple small 2-3 mm nodules (arrows) throughout both lungs in a patient with thyroid cancer.

Facts: Miliary Metastasis

• Uncommon form of pulmonary metastasis
• Most commonly due to thyroid cancer, renal cell carcinoma and melanoma

Pulmonary Metastasis in Thyroid Cancer

• Distant metastasis (lung and bone) found in 10-15% of patients with differentiated thyroid cancer
• Lung metastasis is most frequent in young patients with papillary carcinoma, and lungs are almost the only site of distant metastasis in children
• Variables found to be adversely affected survival: extensive metastasis, older age at metastasis, absent I-131 uptake of metastasis, and moderately differentiated follicular cell carcinoma

Our case: thyroid cancer with miliary metastasis

References:

1. Biersack HJ, Grunwald F. Thyroid cancer, 2nd ed, 2005.

2. Schlumberger MJ. Papillary and follicular thyroid carcinoma. N Eng J Med 1998;338:297-306.

Superficial Thrombophlebitis

Longitudinal US image of the antecubital fossa shows an echogenic clot in the basilic vein (arrows).

Facts: Superficial Thrombophlebitis

• Also known as superficial venous thrombosis
• Presence of thrombus in the lumen of superficial vein, followed by inflammation of the wall and adjacent tissues
• Variable degree of severity, can be in small venous tributaries but can extend into deep veins or, uncommonly, result in pulmonary embolism
• Related to Virchow's triad
• Prodromes of many systemic diseases (neoplasm, arteriopathy, collagen vascular disease) and syndromes (Trousseau, Mondor disease, Lemierre, Buerger disease)

Imaging

• Color Doppler US provides definitive diagnosis by showing clot, uncompressibility, absence of flow

Reference:

Sobreira ML, Yoshida WB, Lastoria S. Superficial thrombophlebitis: epidemiology, physiopathology, diagnosis and treatment. J Vasc Bras 2008;7. Available here.

C Sign of Talocalcaneal Coalition

Fig. 1: Lateral radiograph of the right ankle shows a C sign (yellow dotted line) that extends from the talar dome through the coalition component of the posterior talocalcaneal joint to the sustentaculum tali.
Fig. 2: Coronal reformatted CT image confirms the presence of talocalcaneal coalition (arrows) between the talus (T) and calcaneus (C).

Facts: Tarsal Coalition

• Abnormal bony, cartilaginous or fibrous articulation between two tarsal bones
• Congenital, caused by lack of bony segmentation
• Most common between calcaneus-talus and calcaneus-navicular
• Bilateral in 20% of cases

Imaging

• C sign seen on lateral view when middle facet talocalcaneal coalition is present (as in our case)
• Talar beak is an indirect sign of abnormal talonavicular motion, it is a bony spur from anterior superior aspect of talus
• CT is an excellent method to identify and characterize tarsal coalition

Reference:

Chew FS, Bui-Mansfield LT, Kline MJ. Musculoskeletal Imaging, 2003.

Renal Oncocytoma

Sagittal contrast-enhanced CT image shows a well defined, enhancing mass in the right kidney of a 67-year-old man presenting with hematuria.

Facts: Renal Oncocytoma

• 5% of all adult primary renal epithelial neoplasm in surgical series
• Believed to originate from or differentiate toward type A intercalated cells of the cortical collecting duct
• Men more common than women
• Frequently seen in 7th decade

Imaging Features

• Solitary, well defined mass of renal cortex
• Stellate fibrotic scar can be seen with large tumors
• Spoke-wheel pattern of feeding arteries seen on catheter angiography
• Cannot be differentiated from renal cell carcinoma, and can be associated with RCCs either as hybrid tumors or collision tumors

Our case: Oncocytoma proven by histology. On imaging, this mass cannot be differentiated from RCC and should be investigated as possible RCC until proven otherwise.

Reference:

Prasad SR, Surabhi VR, Menias CO, et al. Benign renal neoplasms in adults: cross-sectional imaging findings. AJR 2008;190:158-164

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Hematosalpinx

Fig.1: Sagittal US image of the pelvis of a 13-year-old girl presenting with acute pelvic pain shows multiple cystic lesions (arrows) behind the uterus (U). These cystic structures have peculiar frondlike structures internally suggesting that they represent a dilated fallopian tube.
Fig. 2: Sagittal T2W MR image confirms the presence of dilated fallopian tube with fluid-fluid levels, suggesting hematosalpinx.

Facts: What Causes Hematosalpinx?

• Tubal pregnancy (most common)
• Endometriosis
• Fallopian tube cancer
• Obstructed vagina resulting in menstrual blood backflow into fallopian tubes

Facts: Isolated Tubal Torsion

• Very rare entity causing lower abdominal pain
• Usually occurs in reproductive age
• Diagnosis rarely made preoperatively
• Imaging findings are adnexal cystic mass, hydrosalpinx, hematosalpinx
• Twisted fallopian tube, if visualized, is a specific sign for tubal torsion. If the ovary is also torsed, the ipsilateral ovary becomes enlarged.

Our case: isolated fallopian tube torsion causing hematosalpinx.

Reference:

1. Park BK, Kim CK, Kim B. Isolated tubal torsion: specific signs on preoperative computed tomography and magnetic resonance imaging. Acta Radiologica 2008;49:233-235.

2. Wikipedia: hematosalpinx