Transcript Medical Student SYB

Medical Student SYB
December 17, 2008
Matt Kulzer MSIV

History
◦ 14yo male with history of Ataxia-Telangiectasia
◦ Presented yesterday with 3 wk h/o chest pain,
headache, low grade fever, and fatigue

Physical Exam
◦ T 38.1, HR 106, RR 20, SpO2 99% on RA
◦ Remainder WNL

Labs
◦ Omitted
Case Overview



WBC 249,000
Anemia/thrombocytopenia
Smear
◦ Preponderance of blasts
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
CXR - Soft tissue density projecting along the right heart border on the AP
view. It appears to be contiguous with the heart border, and there is no
evidence of a posterior mediastinal mass on the lateral view. This could
represent a mediastinal mass rather than prominent ascending aorta. The
former is more likely given high WBC and concern for leukemia. Recommend
comparison to any outside chest radiographs before proceeding to additional
cross-sectional imaging studies.
CT
◦ Heterogeneous anterior mediastinal mass measuring 4.2 x 6 cm in shortest and long
axis. This anterior mediastinal mass abutting the right atrium, right ventricle, SVC, and
descending aorta.
◦ Two adjacent nodular opacities within the posterior basal segment of the right lower
lobe, that are concerning for leukemic infiltrates or metastatic lesions versus infectious
process (in a patient with history of fever).
◦ Marked splenomegaly.
Additional Information/Findings
AR hereditary ataxic disorder
 Patients develop:

◦ progressive cerebellar ataxia
◦ abnormal eye movement
◦ other neurologic disorders (gross motor dysfxn,
LMN weakness, speech/swallowing dysfnx)
◦ oculocutaneous telangiectasias
◦ immune deficiency
◦ leukemias/lymphomas
Ataxia Telangiectasia
Mechanism of DNA
damage
susceptibility in AT
Interaction between cancer
susceptibility genes and DNA repair.
ATM (ataxia-telangiectasia
mutated) senses a double-strand
break in DNA, induced by agents
such as ionizing radiation. ATM and
CHEK2 phosphorylate BRCA1,
promoting its migration to the
break site. The Fanconi's anemia
protein complex (proteins A, C, E,
F, G) triggers the ubiquitination and
co-localization of the Fanconi
protein D2 with BRCA1 at the break
site. BRCA2 carries RAD51, an
enzyme involved in DNA
recombination repair, to the same
site. BRCA1, BRCA2, and RAD51
repair the DNA break by an errorfree recombination mechanism.
RAD51 is a component of cell cycle
check points. (Redrawn from
Venkitaraman AR: A growing
network of cancer-susceptibility
genes. N Engl J Med 348:1917,
2003 and taken from Robbins and
Cotran Pathologic Basis of Disease
7E on December 16, 2008.)
Identify the lesion
 Location

◦ AP
◦ LATERAL!!!!

Know the differentials based on
location/age of pt
Mediastinal Masses: Approach
Mediastinal
Masses: Anatomy
Anterior Mediastinal Masses
DDx:
 Thymic Masses
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

◦
◦
◦
◦
◦
◦
Lymphoma*
Thymoma*
Thymic ca
Thymolipoma
Thymic cyst
Thymic hyperplasia
◦
◦
◦
◦
Thyroid
Thyroid
Thyroid
Thyroid


Or, simplified:
The 4 T’s:
◦
◦
◦
◦
Thymoma
Thyroid lesions
Teratoma
T-cell lymphoma
Thyroid Masses
goiter*
cyst
adenoma
ca
Germ Cell Tumors
◦ Teratoma/teratocarcinoma*
◦ Seminoma
◦ Mixed Germ cell tumors

* indicates most common
Mediastinal Masses: Anterior

Middle Mediastinal Masses DDx:
◦
◦
◦
◦
◦
◦
◦
◦
◦
◦
◦
◦
◦
◦
◦
◦
◦

Goiter
Lymphadenopathy
Mets*(lung ca most common)
Lymphoma/leukemia*
Granulomatous infection
Sarcoidosis
Inhalational lung disease (i.e., silicosis,
berylliosis, coal workers’
pneumoconiosis)
Castleman’s disease
Aortic abnormalities: aneurysm*,
dissection*, traumatic rupture
Bronchopulmonary foregut cysts
Tracheal tumor
Esophageal abnormalities: neoplasm,
achalasia
Hiatal hernia* (with air/fluid level)
Cardiac tumor
Left ventricle
aneurysm/pseudoaneurysm
Pulmonary artery aneurysm
Neurogenic tumor of vagus nerve

Or Simplified:
◦ Thoracic aortic
aneurysms
◦ Hematomas
◦ Neoplasms
◦ Adenopathy
◦ Esophageal lesions
◦ Diaphragmatic
hernias
◦ Duplication cysts
* indicates most common
Mediastinal Masses: Middle

Posterior Mediastinal
Masses DDx:
◦ Neurogenic tumors*
(peripheral nerve,
sympathetic ganglion,
parasympathetic
involvement)
◦ Primary or metastatic bone
tumor of thoracic spine
◦ Osteomyelitis or paraspinal
abscess of thoracic spine
◦ Extramedullary
hematopoesis


Or simply:
◦ 90% Neurogenic
 Young: neuroblastoma
 Adult: neurofibromas,
schwannomas,
ganglioneuromas
◦ Others:




Hernias
Other neoplasms
Hematomas
Extramedullary
hematopoesis
* indicates most common
Mediastinal Masses: Posterior
Kumar, et al (2005). Molecular Basis of Cancer,
Robbins and Cotran Pathologic Basis of Disease 7E.
Philadelphia: Elsevier
 Mettler, FA (2005). Mediastinal Masses, Essentials of
Radiology. Philadelphia: Elsevier
 Puneet, et al (2008). Ataxia-telangiectasia, Up To
Date. Retrieved from
http://www.utdol.com.proxy1.athensams.net/online/c
ontent/topic.do?topicKey=ped_neur/9337&selectedTit
le=1~150&source=search_result
 Torrigan, DA and Wallace, TM (2006). Mediastinal
Masses. Pretorius, ES and Solomon, JA (Eds.),
Radiology Secrets Second Ed.). Philadelphia: Elsevier.

References