Isolated Epitrochlear Filarial Lymphadenopathy: Cytomorphological Diagnosis of an Unusual Presentation
Priya SAHU1, Prajwala GUPTA1, Minakshi BHARDWAJ1 , CK DURGA2
1Department of Pathology, Post Graduate Institute of Medical Education and Research, Dr. Ram Manohar Lohia Hospital, NEW DELHI, INDIA
2Department of Post Graduate Institute of Medical Education and Research, Dr. Ram Manohar Lohia Hospital, NEW DELHI, INDIA
Keywords: Filariasis, Microfilaria, Lymph node, Cytology
Filariasis is a major public health problem in tropical countries like India. Despite the large number of people at risk, detection of eggs with
or without larva (microfilaria) on fine-needle aspiration cytology is very unusual, especially in an uncommon site or incidentally detected in
clinically unsuspected cases of filariasis with the absence of microfilariae in the peripheral blood. A 19-year-old male presented with swelling
over medial aspect of left arm (just above the elbow), with no other specific signs and symptoms. Fine needle aspiration cytology revealed an
adult gravid female filarial worm in a background of reactive lymphoid cells and lymphohistiocytic clusters. We report a case with elaborate fine
needle aspiration cytology findings of filarial worm infestation with unusual presentation of isolated epitrochlear lymph node involvement in a
clinically unsuspected case and recommend clinicians and pathologists to consider a high index of suspicion for such infections at uncommon
sites especially in endemic territories, as early diagnosis and treatment prevent the more severe manifestations of disease.
Filariasis has been a major public health problem in
tropical and subtropical countries 1
. Microfilaria have
been reported at various sites involving lymphatic systems
and subcutaneous tissue, though meagre cases have been
reported of filarial infestation with epitrochlear lymph
nodes involvement 2
Lymphatic vessels of the definitive host (man) harbours the
adult worms of Wuchereria bancrofti and microfilaria are
released in peripheral blood 3. However, all components
of filarial worm infestation such as adult filarial worm
with eggs and microfilaria in varying stages are rarely
found together on fine needle aspiration cytology (FNAC)
of lymph node swellings. We present one such elaborate
cytomorphological findings of filarial worm infestation in
a case with isolated involvement of an epitrochlear lymph
A 19-year-old male, resident of Bihar, presented to the
FNA clinic with complaints of a painless swellings over
the medial aspect of the left arm just above the elbow for 8
months, which had gradually increased in size. He had no
complaints of fever or any other swelling in the body. General
examination was normal and did not reveal any palpable
peripheral lymphadenopathy. On local examination there
were two swellings, located superficially on the medial aspect of the left arm just above the elbow, measuring 2x2cm
and 1x1cm (Figure 1
). The swellings were firm, mobile and
non-tender with normal appearing overlying skin. FNAC
was done and the air dried and alcohol fixed slides were
stained with Giemsa and Papanicoloau stain respectively.
Cytopathological examination of these slides revealed
gravid segments of adult filarial worm and embryonated
eggs (Figure 2A,B
) with various stages of microfilaria
(coiled and uncoiled) (Figure 2C
). The microfilaria seen
were sheathed with absence of nuclei at tip (W. bancrofti)
). Background was haemorrhagic and showed
focal reactive lymphoid cells and lymphohistiocytic
clusters. (Figure 2D
) On FNAC, a diagnosis of parasitic
infestation with filarial lymphadenopathy was made.
Complete blood count revealed Hb.-13.2g/dL, TLC- 4700/
mm3 and differential count revealing eosinophilia (14%)
with absolute eosinophil count of 648/mm3 (normal range-
30-350/mm3). Peripheral blood did not reveal microfilaria.
The patient was started on Diethylcarbamazine citrate
(DEC) and on follow up the swelling was reduced.
Click Here to Zoom
|Figure 1: Swelling over medial aspect of left arm above elbow (red
Click Here to Zoom
|Figure 2: A) Adult gravid segment of filarial worm packed with embryonated eggs. (MGG; x100). B) Adult filarial worm segment
with coiled forms of microfilaria (PAP; x100). C) Embryonated egg, coiled and uncoiled forms of sheathed microfilaria (MGG; x400).
D) Focally the smears had lymphocytes and a lymphohistiocytic cluster and the arrow shows coiled microfilaria. (PAP; x40).
Filariasis is an endemic problem in many parts of India
such as Assam, West Bengal, Bihar, Odisha, Uttar
Pradesh, Madhya Pradesh, Tamil Nadu and Jharkhand 4
there remains limited reliable information on the current
epidemiology of filariasis in mainland Southeast Asia.
We conducted a systematic review and meta-analysis of available literature to assess the recent and current
prevalence of infection and morbidity in the region. Fiftyseven
journal articles and reports containing original
prevalence data were identified, including over 512,010
participants. Data were summarised using percentage prevalence estimates and a subset combined using a random
effects meta-analysis by country and year. Pooled estimates
for microfilaraemia, immunochromatographic card
positivity and combined morbidity were 2.64%, 4.48% and
1.34% respectively. Taking into account pooled country
estimates, grey literature and the quality of available data,
we conclude that Lao People’s Democratic Republic (PDR.
In endemic communities, filariasis is usually asymptomatic
and symptoms are caused by progressive lymphatic
vascular dilatation 1
. Humans are the definitive host
and infection is transmitted by mosquitoes. It can cause
lymphatic filariasis or non-lymphatic filariasis involving
subcutaneous tissue or serous cavities. Lymphatic filariasis
represents about 25-30% of all cases of filariasis, caused
most commonly by Wuchereria bancrofti, followed by
Brugia malayi or Brugia timori 5
. These worms occupy
the lymphatic system, including the lymph nodes 6
Serous cavity filariasis is caused by Mansonella species.
In cases of lymphatic filariasis, it has a predilection for
lymphatic system of the lower limbs and male genitalia,
producing episodic funiculitis, epididymitis and orchitis
. Filariasis accounts for 0.047% of all cases of lymph
node swellings with a predilection for inguinal and axillary
lymph nodes and causes retrograde lymphangitis 5,7,8
Microfilariae have been incidentally detected and reported
in fine needle aspirates of various visceral sites like the
breast, thyroid, spleen, ovarian fluid and bone marrow. Rare
reports of microfilaria have been noted in the urine and
in an upper arm cystic swelling in clinically unsuspected
cases of filariasis with the absence of microfilariae in the
peripheral blood 1,8,9.
Epitrochlear lymph nodes may be enlarged as a part of
generalized lymphadenopathy and isolated enlargement is
seldom seen. Tuberculosis, cat scratch disease, leprosy and
leishmaniasis are a few reported benign causes of isolated
epitrochlear lymph node enlargement; malignant causes
include lymphoma and malignant melanoma 2. After
extensive literature search, meagre reported cases were
found of filarial involvement of epitrochlear lymph nodes
Our case is an addition to unusual sites of filarial involvement
as an isolated epitrochlear lymph node enlargement.
Moreover in the present case, all the components of filarial
worm infestation consisting of gravid female worm with
eggs and different stages of microfilaria were demonstrated
We reiterate that the demonstration and identification of
different parasitic components in cytology smears play a
significant role in early diagnosis of the disease. This would
prompt the clinicians for instituting a specific treatment
and consider a high index of suspicion for filariasis at
uncommon sites especially in endemic areas.
CONFLICT of INTEREST
The authors declare that they have no competing interest.
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