Lymph nodes - not lymphoma
Infectious / parasitic disorders
Granulomatous lymphadenitis with microfilaria

Author: Sajna V.M. Kutty, M.D. and Nat Pernick M.D.

Revised: 9 July 2018, last major update December 2017

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Granulomatous lymphadenitis with microfilaria

Cite this page: Kutty, S.V.M., Pernick, N. Granulomatous lymphadenitis with microfilaria . PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lympnodesglwm.html. Accessed October 20th, 2018.
Definition / general
  • Filariasis is due to infection by threadlike nematodes of the family Filarioidea
  • Filarial infection can cause lymphedema of the limbs (elephantiasis), genital disease (hydrocele, chylocele and swelling of the scrotum and penis) and recurrent painful acute attacks (World Health Organization > Lymphatic Filariasis, retrieved 15 December 2017)
Essential features
  • Wuchereria bancrofti accounts for up to 90% of cases
  • Diagnosis is typically made by identifying microfilariae in peripheral blood smears
  • Rarely microfilariae are coincidentally detected in FNAC in association with various inflammatory and neoplastic lesions
  • Wuchereria bancrofti can be identified by its sheath and multiple, coarse, discrete nuclei extending from head to tail except in the small terminal portion of the caudal end
Epidemiology
  • Major public health problem in India, China, Indonesia, Africa and the Far East
Pathophysiology
  • Wuchereria bancrofti accounts for up to 90% of cases
  • Adult worms lodge in the lymphatics, where females release larvae (microfilaria) which periodically circulate in the blood, and are occasionally ingested by feeding mosquitoes
  • Microfilaria mature in the mosquitoes before becoming infective, and are spread to new humans during mosquito feeding
Clinical features
  • Humans are the exclusive host of infection with W. bancrofti
  • Many infected individuals remain asymptomatic and serve as potential sources of infection
  • Virtually all infected people have subclinical lymphatic damage, and up to 40% have kidney damage with proteinuria and hematuria
Diagnosis
  • Diagnosis is typically made by identifying microfilariae in peripheral blood smears
  • Rarely microfilariae are coincidentally detected in FNAC in association with various inflammatory and neoplastic lesions (J Cytol 2010;27:78, J Cytol 2017;34:43)
  • Finding microfilaria in cytosmears is rare
Treatment
  • Treatment consists of multiple doses of albendazole and ivermectin to the entire at risk population, in addition to mosquito control
Microscopic (histologic) description
  • Wuchereria bancrofti can be identified by its sheath and multiple, coarse, discrete nuclei extending from head to tail except in the small terminal portion of the caudal end
Microscopic (histologic) images

Images hosted on PathOut server:

Contributed by Sajna VM Kutty, M.D., Aster MIMS, Kerala (India)

Case of the Week #446

Board review question #1
Which statement regarding microfilarial infection is true:

A. Infections are associated with exposure to animals
B. Most patients have non-specific symptoms
C. Diagnosis is made by culture
D. Mosquito control is an important part of treatment
E. Quarantine is an important component of treatment
Board review answer #1
D. Mosquito control is an important part of treatment