Testis and epididymis
Paratesticular tumors
Lymphoma

Author: Swapnil U. Rane, M.D. (see Authors page)
Editorial Board review by Debra Zynger, M. D.

Revised: 19 April 2016, last major update April 2014

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Lymphoma [title] testis
Epidemiology
  • Paratesticular lymphoma is rare without testicular involvement
  • Inadequate staging information in many reported cases
  • Involves epididymis in 60% and spermatic cord in 39% of cases (Am J Surg Pathol 1994;18:376)
  • Lymphomas comprise 2% of spermatic cord tumors (J Urol 1965;94:445)
  • Most patients are elderly, although younger patients have been reported
Sites
  • Epididymis and spermatic cord are most common location; involvement of tunica or lymphoma arising in cysts/hydroceles is rare
Pathophysiology / Etiology
  • Precise pathophysiology of primary paratesticular lymphomas is unknown
  • Occurrence in tunica, cysts or hydroceles suggests role of chronic inflammation, demonstrated by EBV DNA in these cases (Am J Surg Pathol 2012;36:1074, Mod Pathol 2010;23:493)
  • Most cases are diffuse large B cell lymphoma; other reported types (uncommon) are follicular, Burkitt, plasmacytoma, NK-T cell lymphoma
  • Single case of transplacental transmission of NK-T cell lymphoma localizing to paratesticular region (Blood 2011;117:6046)
  • Specific translocations are seen with each histological subtype
Clinical Features
  • Painless scrotal / paratesticular swelling of variable duration
  • May have long standing history of hydrocele
  • Variable B symptoms
Diagnosis
  • Histological examination with immunohistochemistry and FISH/PCR for translocations as necessary
  • Systemic workup for disease staging
  • Identification at frozen section can prevent unnecessary orchiectomy (Hum Pathol 2012;43:1514)
  • Misdiagnoses occur including mistaking lymphoma for seminoma, embryonal carcinoma and embryonal rhabdomyosarcoma (Arch Pathol Lab Med 2007;131:1040)
Radiology Description
  • Radiology helpful to delineate extent of disease and for staging workup, not for diagnosis
  • Lesion is usually diffuse without sharp boundaries
Prognostic Factors
  • Poor prognosis in general, due to extra-lymphatic disease and high incidence of CNS spread
  • Prognostic factors (same as lymphomas in general and specific to each histological type): age, ECOG status, LDH level, stage, association with HIV and other chronic infections
  • Mean overall survival is 32-96 months for testicular and paratesticular lymphoma (Arch Pathol Lab Med 2007;131:1040)
Case Reports
Treatment
  • Biopsy for diagnosis followed by systemic chemotherapy based on type of lymphoma; radiotherapy to prevent local recurrence
Clinical Images
Images hosted on other servers:

MRI of paratesticular lymphoma in infant

Paratesticular plasmacytoma

MALT lymphoma

Gross Description
  • As a nodule, lesion is fleshy and homegenous
  • No confluent necrosis or hemorrhage (Arch Pathol Lab Med 2007;131:1040)
  • As a nodule, lesion is fleshy with variable necrosis or hemorrhage
Gross Images
Image hosted on other servers:

Well encapsulated

Micro Description
  • Usually diffuse sheets of high grade cells with mitotic figures and apoptotic cells
  • Morphology depends on type of lymphoma
Micro Images
Images hosted on other servers:

Various images

NK-T cell lymphoma in infant (transplacental spread)

Large, atypical and polymorphic cells

CD79a, CD3

Cytology Description
  • Cellular smears with scattered single high grade lymphoid cells having prominent nucleoli, frequent mitosis and apoptosis
Immunohistochemistry
  • Full immunohistochemistry workup is essential for diagnosis: B, T cell markers, NK cell markers (if needed), BCL2, BCL6, CD10, Ki67, EBV LMP, EBNA, etc.
Molecular / Cytogenetics Description
  • Translocation studies may be essential in some cases
Differential Diagnosis
  • Inflammatory pseudotumor / inflammatory myofibroblastic tumor: mixed population of cells as compared to the uniform population of high grade cells in non-Hodgkin lymphoma
  • Seminoma: similar gross appearance; microscopically has branching fibrous septae, cells with distinct borders, more cytoplasm and an intratubular germ cell neoplasia in situ component
  • Embryonal carcinoma: usually has more necrosis and hemorrhage grossly and microscopically; has architectural features such as papillae or trabeculae, higher degree of pleomorphism and an intratubular germ cell neoplasia in situ component
  • Embryonal rhabdomyosarcoma