This is a 13 year old male with a chief complaint of 
bilateral scrotal swelling.  The swelling began a month 
ago and has been gradually increasing.  It is 
associated with mild discomfort but no pain.  He 
complains of fatigue and two episodes of epistaxis in 
the last month.  There is no history of trauma or voiding 
difficulties.  Review of systems are otherwise negative 
for fever, chills, headache, cough, abdominal pain, 
weight loss or night sweats.  He has no other significant 
past medical history.
     Exam:  VS T 36.7 (oral), P 84, R 18, and BP 110/70.  
He is healthy appearing and comfortable.  He has 
significant bilateral scrotal swelling with the skin taut 
and erythematous.  The right hemiscrotum measures 8 
cm x 4 cm.  The left hemiscrotum is 8.5 cm x 4 cm.  The 
scrotal swelling is firm, non-tender and does not 
transilluminate.  There is no clinical evidence of 
organomegaly, lymphadenopathy or an abdominal 
mass.  The remainder of the physical examination is 
normal.
     His WBC is 4,300 with 24% neutrophils, 64% 
lymphocytes and 3% eosinophils.  A review of the 
peripheral smear is negative for blast cells.  Since 
systemic diseases such as lymphoma may present as a 
testicular mass, a chest radiograph was obtained.

View his CXR.



     His chest radiographs reveal an anterior mediastinal 
mass.  The PA view shows a widened mediastinum.  
Note the abnormal contour of the mediastinal shadow 
above the heart.   The lateral view shows a solid tissue 
density in the region anterior and superior to the heart.  
In infants, this region is filled with a thymic density.  
However, in children, teens and adults, this region 
should be occupied by lung tissue.  A solid tissue 
density is suggestive of a mediastinal mass (or right 
ventricular enlargement).
     The suggestion of a mediastinal mass in conjunction 
with testicular swelling suggests the presence of a 
neoplastic process.  The common causes of testicular 
swelling with a mediastinal mass include lymphoma, 
leukemia and germ cell tumors. 

     His CBC does not show any signs of leukemia.  Beta 
HCG and Alpha-fetoprotein, both markers for germ cell 
tumors, are normal.  Testicular biopsy demonstrates 
the presence of a lymphoblastic lymphoma.  Bone 
marrow examination does not show marrow 
involvement.

Discussion
     Lymphoma is the third most common neoplasm of 
childhood after leukemia and central nervous system 
(CNS) tumors (1).  It is the most common anterior 
mediastinal mass accounting for a quarter of all 
mediastinal masses (2). 
     Pediatric Non-Hodgkin's lymphoma (NHL) accounts 
for approximately 10% of cancers in children and 
adolescents (3).  The peak age of presentation is 9 
years (2), and males outnumber females 3 to 1 (4).  
Non-Hodgkin's lymphomas can usually be placed in 
one of the three major subgroups:  Burkitt's lymphoma, 
lymphoblastic lymphoma and large cell lymphoma (3).
     Patients with lymphoblastic lymphomas commonly 
manifest as an intrathoracic tumor, particularly as a  
mediastinal mass (50% to 70%) and often have pleural 
effusions (4).  More than 70% of the patients have 
disseminated disease at the time of presentation (2).
     Mediastinal masses are the most common thoracic 
masses in children.  Approximately 30% develop before 
age 12.  Approximately 30% occur in the anterior, 30% 
in the middle, and 40% in the posterior compartment of 
the mediastinum (2).
     The diagnosis of lymphoma should be made 
expeditiously, as it can disseminate rapidly.  Diagnostic 
studies should include complete blood count, 
sedimentation rate, serum LDH, Beta HCG, 
alpha-fetoprotein and a chest radiograph.  Early 
involvement of an oncologist is essential in order to 
facilitate an appropriate work-up.

Teaching points
     1.  Any patient with painless testicular swelling not 
associated with underlying inflammation, trauma or 
infection should have a chest radiograph to identify the 
presence of a mediastinal mass or parenchymal lung 
lesions.
     2.  The first step in evaluating a mediastinal mass 
lesion is to place it in one of the three mediastinal 
compartments, since each has its own differential 
diagnosis.  The most common lesions in the anterior 
mediastinum are thymoma, lymphoma and teratoma.  
The most common masses in the middle mediastinum 
are vascular masses, lymph node enlargement from 
metastases or granulomatous disease and 
pleuropericardial and bronchogenic cysts.  In the 
posterior mediastinum, neurogenic tumors, 
meningocele, meningomyelocele, gastroenteric cysts 
and esophageal diverticula are commonly found (5).  
Neurogenic tumors comprise 90% of the posterior 
mediastinal masses in the pediatric age group.  
Neuroblastoma is by far the most common followed by 
ganglioneuroblastoma and ganglioneuroma.  
Mediastinal neuroblastoma is also associated with a 
more favorable prognosis when diagnosed in a child 
before 1 year of age (2).
     3.  After identification of a mediastinal lesion on a 
conventional radiograph, CT or MRI is the preferred 
modality for further evaluation of the middle and 
anterior mediastinum, whereas MRI is definitely the 
preferred modality for posterior mediastinal lesions, 
since most are neurogenic lesions which delineate 
better with MRI because of its multiplanar capabilities 
(2).

References
     1.  Gilchrist  GS.  Lymphoma.  In:  Behrman RE, 
Kliegmman RM, Jenson HB (eds).  Nelson Textbook of 
Pediatrics, 16th edition.  Philadelphia, W.B. Saunders 
Company, 2000, pp1548-1552.
     2.  Blickman JG.   Pediatric Radiology - The 
Requisites.  St. Louis, Mosby, 1994, pp36-41.
     3.  Philip T, Bergeron C, Frappaz D.  Management 
of paediatric lymphoma.  Bailliere's Clinical 
Haematology 1996;9(4):769-797.
     4. Shad A, Magrath I.  Malignant Non-Hodgkin's 
Lymphomas in Children.  In:  Pizzo PA, Polack DG 
(eds).  Principles and Practice of Pediatric Oncology, 
3rd edition, Philadelphia, Lippincott-Raven 
Publishers,1997, pp545-587.
     5.  Light RW.  Disorders of pleura, mediastinum and 
diaphragm.  In:  Fauci AS, Braunwald E, Isselbacher 
KJ, et al (eds).  Harrison's Principles of Internal 
Medicine, 14th edition.  New York, McGraw-Hill Health 
Professions Division, 1998, pp1472-1476.