Neurofibromatosis type I syn NF1 von Recklinghausen

disease): This autosomal-dominant congenital disease manifests with numerous nodular, soft neurofibromas of the central, peripheral, and autonomic nerve system (Fig. 8.78). The famous cafe-au-lait colored skin spots are characteristic. In addition, gliomas of the optic nerve and dysplasias of the sphenoid bone may be present. The neurofibromas can transform into malignant neurofibrosarcomas in up to 10 % of patients. Rapidly growing lesions are highly suspicious for that reason.

Amyloid: Amyloidosis can infrequently cause soft tissue tumors that have nonspecific MR signal intensity between muscle and cartilage on both Tl - and T2-weighted images. As with lymphoma today and syphilis in the past, one should be prepared for the unusual. The question "Could this be amyloid?" has a resounding effect in utterly complicated cases and—if used sparingly and with caution— provides the radiologist with a minute to catch his or her breath in discussions with suddenly hesitant clinical colleagues.

Mafucci syndrome (see p. 123): In this entity hemangio-mas are seen parallel to the already described multiple enchondromas. They typically contain phleboliths, which is why this diagnosis can be diagnosed on plain radiographs.

NowJoey thinks about all tumors with a typical signal behavior in MRI:

Lipoma, liposarcoma: A pure lipoma demonstrates a typical high, fat-equivalent signal on Tl-weighted and fast spin echo T2-weighted images just like subcutaneous fat tissue. With the so-called "out of phase technique," the fat content of the tumor can be proved. If the interior of the lesion appears homogeneous, a benign process is more likely. If a tumor is inhomogeneous, has irregular

I The Case of Arnold Schwortenbakker

I The Case of Arnold Schwortenbakker

Pictures Liposarcoma Arms
Fig. 8.77 This axial MR image of Mr. Schwortenbakker's arm above the right shoulder joint inT1-weighting (a) and T2-weighting (b) should be more than sufficient for your diagnosis! What soft tissue tumors do you have to contemplate?
Inside Neurofibro Tumor

Fig. 8.78 Multiple neurofibromas are located along the course of the neurovascular bundle.

images can, however, also be caused by fast blood flow or calcifications in a tumor.

Fig. 8.78 Multiple neurofibromas are located along the course of the neurovascular bundle.

margins, invades the neighborhood, and also contains fat (Fig. 8.79), a liposarcoma is probable and has to be ruled out through biopsy or excision. Lack of fat, however, does not exclude a liposarcoma.

Fibrosarcoma, malignant fibrous histiocytoma: Tumors with a high proportion of fibrous tissue such as fibrosarcoma (Fig. 8.80) or malignant fibrous histiocytoma (MFH) may show a relatively low signal on both Tl-weighted and T2-weighted MR images. The reason is the paucity of protons in this tissue, which are needed for imaging in conventional magnetic resonance tomography. A low signal both in Tl-weighted and T2-weighted

I Liposarcoma

Liposarcoma Mesentery
Fig. 8.79 This CT image through the upper pelvis shows a large fatty tumor within the mesentery that is septated by fibrous strands of differing caliber. Histology confirmed the radiological suspicion of a liposarcoma.
Histology Fibrous Tissue Bon Emarrow
Fig. 8.80 The coronal MR sections through both knee joints document a large signal-free structure along the left joint. This signal type is typical for fibrous, water-deprived tissue. Size, configuration, and signal suggest a malignant fibrous tumor here—a fibrosarcoma.

images can, however, also be caused by fast blood flow or calcifications in a tumor.

Myositis ossificans: The main characteristic of a myositis ossificans is the overshooting ossification of the soft tis-sues—frequently after a soft tissue trauma and resulting intramuscular hematoma. It is particularly pronounced if the patient has been in coma. The diagnosis is usually made from the plain radiograph (Fig. 8.81).

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