Clinical case

T. Guarneri

Cattedra di radiologia – Università di Brescia

D.F. 20 ys, F

Physiological anamnesis:

Good general health conditions

Close pathologic anamnesis: On May 2011 she has a car accident

Chest XR (03-05-2011)

NEGATIVE?

27.05.2011: abdominal pain, no fever or other symptoms

Ultrasound

Heterogeneously hypoechoic mass (52 x 25 mm) in the paraspinal and presacral regions

ADENOPATHY?

CT (30-05-2011)

Chest

.

Abdomen

Neurofibromatosis Type 1(von Recklinghausen disease)

- one of the most common genetic disorders (prevalence: 1:3000)

- mutation of the NF1 gene (chromosome 17): no control of cellular proliferation

50% positive family history

50% sporadic new mutations

Diagnostic Criteria for NF1

The patient should have two or more of the following:1. Six or more cafe´ au lait spots 1.5 cm or larger in postpubertal individuals 0.5 cm or larger in prepubertal individuals2. Two or more neurofibromas of any type or one or more plexiform neurofibromas3. Freckling in the axilla or groin4. Optic gliomas (tumor of the optic pathway)5. Two or more Lisch nodules (benign hamartomas)6. A distinctive bony lesion Dysplasia of the sphenoid bone Dysplasia or thinning of long bone cortex7. First degree relative with NF1

Classification of Abdominal Neoplasms in NF1

● Neurogenic neoplasmsNeurofibromaPlexiform neurofibromaMalignant peripheral nerve sheath tumorGanglioneuroma● Neuroendocrine neoplasmsCarcinoidPheochromocytomaParaganglioma / Gangliocytic paraganglioma● Non neurogenic gastrointestinal mesenchymal neoplasmsGastrointestinal stromal tumorLeiomyoma / Leiomyosarcoma● Embryonal tumorsRhabdomyosarcomaNeuroblastomaWilms tumor● Miscellaneous tumorsGastrointestinal adenocarcinomaPancreatic adenocarcinomaBiliary adenocarcinoma

The lifetime risk of developing an MPNST (malignant peripheral nerve sheath tumor) for a person with NF1 is 4-5%.

Neurofibromas are the hallmark lesion of NF1

65% asymptomatic 35% symptomatic:- palpable abdominal mass- pain along the distribuition of the nerve- GI mucosal involvement (hematemesis, melena, hematochezia)- intestinal obstruction (nausea, vomiting,abdominal distension)-bladder involvement (urinary frequency, incontinence, urgency, abdominal pain)

Radiologic features

In the thorax, neurofibromas tipically appear as well-marginated, smooth, round or elliptic masses in the paravertebral regions or along the course of the vagus, phrenic, recurrent laryngeal or intercostal nerves.Plexiform neurofibromas are extensive fusiform or infiltrating masses that tend to surround mediastinal vessels with loss of normally visible fat planes.

In the abdomen, neurofibromas are located in the paraspinal (symmetric or asymmetric masses within or adjacent to the psoas muscle) and presacral regions, along the course of the lumbosacral plexus.Mesenteric plexiform neurofibromas manifest as multiple nodules or infiltrating lesions of the wall of the intestine.The lesions in the perirectal region can infiltrate the perirectal fat and the pelvic structures.

US: heterogeneous in echotexture with variable through transmission (e.g. retroperitoneal and paraspinal neurofibromas), homogeneously or heterogeneously hypoechoic in echotexture (e.g. mesenteric neurofibromas)

CT: neurofibromas are iso- or hypoattenuating masses, compared with adjacent soft tissue (20-25 HU on nonhenanced scans, 30-35 HU on intravenous contrast –enhanced scans). They have variable contrast enhancement and may calcify.

MR: low signal intensity on T1-weighted images heterogeneous high signal intensity on T2-weighted images corresponds to areas of cystic degeneration or myxoid matrix

MR

T1 T2

NF1: a diagnostic mimicker at CT

● Lymphoma● Tuberculosis● Infection (Mycobacterium avium-intracellulare complex)● Sarcoidosis

● Esophageal cancer● Invasive thymoma

● Fibrous pleural tumors● Metastatic pleural implants● Extramedullary hematopoiesis

● Pancoast tumor

● Solitary pulmonary nodule

● Pulmonary adenocarcinoma● Metastatic adenocarcinoma● Plasmacytoma● Pulmonary infection (nocardiosis, actinomycosis)

● Metastatic disease● Soft-tissue sarcoma● Chondrosarcoma

● Vertebral metastatic disease● Myeloma● Tuberculous spondylitis

● Bilateral adrenal masses

● Celiac adenopathy

● Retrocrural adenopathy

● Psoas abscess

● Rectal inflammatory or malignancy

● Iliac and obturator adenopathy

● Primary bone malignancies (giant cell tumor, chordoma, lymphoma) or metastasis

● Primary or metastatic soft-tissue sarcoma

● Imaging studies are indicated only when patients are symptomatic. ● Surgery is currently the only treatment option for most of the lesions in NF1. ● Chemotherapy and radiation therapy are recommended only for the treatment of the malignant tumors.

Treatment

Bibliography

● Fortman BJ, Kuszyk BS, Urban BA, Fishman EK, “Neurofibromatosis Type 1: A Diagnostic Mimicker at CT”. RadioGraphics 2001; 21:601-612.● Biondetti PR, Vigo M, Flore D, et al. “CT appearance of generalized von Recklinghausen neurofibromatosis”. J Comput Assist Tomogr 1983; 7:866–869.● Levy AD, Patel N, Dow N, Abbott RM, Miettinen M, Sobin LH, “From the Archives of the AFIP:Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation”. RadioGraphics 2005; 25:455–480.● Braunwald e, Fauci AS, Kasper DL,Hauser SL, Longo DL, Jameson JL, “Harrison: Principi di Medicina Interna”. Ed. McGraw-Hill 2002.● Tonsgard JH, “Clinical Manifestations and Management of Neurofibromatosis Type 1” Semin Pediatr Neurol 2006; 13:2-7