Cytological diagnosis of microfilariae in filariasis endemic areas of eastern Uttar Pradesh.

BACKGROUND: Filariasis is a major health problem in tropical countries including India. Fine needle aspiration cytology plays an important role in prompt recognition of disease. AIM: To assess the role of fine needle aspiration cytology (FNAC) in diagnosis of filariasis at all possible sites.
MATERIALS AND METHODS: Total 250 cases of superficial swellings at various sites were subjected to fine needle aspiration cytology.
RESULTS: Out of 250 cases, 24 cases of filariasis were detected which include breast lumps (8 cases), lymph nodes (6 cases), scrotal swellings (4 cases), thyroid swellings (3 cases), soft tissue swellings (2 cases) and ascitic fluid (1 case). Eosinophilia was present in 8 out of 24 cases with a percentage ranging from 12-24%. Significant adherence of inflammatory cells and macrophages to microfilariae was present in 3 out of 24 cases.
CONCLUSIONS: In endemic areas, it should be considered one of the differential diagnoses of a superficial swelling. Careful screening of FNAC smears help in detecting microfilaria even in asymptomatic patients and thus plays a significant role in recognition of the disease and institution of specific treatment.

Introduction

Filariasis is a global problem. It is a major social and economic scourge in tropics and subtropics of Africa, Asia, Western Pacific and parts of America affecting over 120 million people in 80 countries.

The problem is increasing every year due to gross mismanagement of the environment. The disease is endemic all over India especially in Uttar Pradesh, Bihar, Jharkhand, Andhra Pradesh, Orissa, Tamil Nadu, Kerala and Gujarat.

There are at least six million attacks of acute filarial disease per year and 45 million persons are currently having one or more chronic filarial lesions.[1]

A majority of infected individuals in filarial endemic communities are asymptomatic. Conventional mode of diagnosis of filariasis is by demonstration of microfilaria in peripheral blood smear. Despite high incidence, it is infrequent to find microfilariae in fine needle aspiration cytology (FNAC) smears and body fluids. The literature contains a few reports of microfilariae found in various locations including thyroid nodule,[23] skin and soft tissue swelling,[24] epididymis,[5] breast,[26-8] salivary gland,[9] cervicovaginal smear,[10] ovarian cyst,[10] urine,[1011] lymph node,[2312] and effusion fluids.[313]

The aim of present study was to assess the role of FNAC in diagnosis of filariasis in asymptomatic patients having superficial lumps.

Materials and Methods

The study was conducted at the Department of Pathology in collaboration with the Departments of Medicine and Surgery at B.R.D. Medical College, Gorakhpur during a period of two years i.e. 2006-2007.

A total of 250 cases, with age ranging from 15-80 years, having swellings at various sites were included in the present study. All these patients were thoroughly examined and routinely investigated. Aspiration was made by technique of Martin and Ellis.[14] In case of cystic lesions, cyst content was aspirated and smears prepared from cyst fluid after cytocentrifugation were studied along with the aspiration performed from cyst wall. These smears were wet fixed immediately in 95% alcohol and stained by hematoxylin and eosin and Papanicolaou stain. Air dried smears were stained by May-Grünwald Giemsa stain.

Results

This study was conducted on 24 cases of filariasis diagnosed on routine FNAC material from various sites. Out of these 24 cases, maximum cases of filariasis were reported in breast swelling (eight cases), followed by lymph nodes (six cases), scrotal swellings (four cases), thyroid swellings (three cases), soft tissue swellings (two cases) and ascitic fluid (one case).

Clinical presentations of these cases were variable which included swelling, pain, fever and erythema [Table 1].

Table 1

Showing clinical profile, cytological findings and associated conditions of 24 cases

Smears revealed sheathed microfilariae, tails of which were free from nuclei and many had graceful curves.

Eosinophilia was present in eight out of 24 cases. The percentage ranged from 12 to 24. Thick and thin blood smear examination of nocturnal venous blood revealed microfilariae of Wuchereria bancrofti in three out of 24 cases.

Microscopic examination of breast swellings showed sheathed microfilaria along with few groups of benign ductal epithelial cells, myoepithelial cells, bare nuclei, few fragments of fibrofatty tissue and inflammatory cells comprising of eosinophils and neutrophils [Figure 1]. Two cases of breast lumps showed epithelioid non-necrotising granuloma without giant cells and plasma cells.

Figure 1

FNAC smear of breast swelling showing sheathed microfilaria along with inflammatory cells

Thyroid aspirates revealed few groups of follicular cells in the background of colloid. In between follicular groups, sheathed microfilariae along with macrophages and eosinophils were seen.

Aspirate from scrotal swelling showed numerous coiled and uncoiled sheathed microfilariae along with neutrophils, eosinophils and few lymphocytes [Figure 2].

Figure 2

FNAC smear of scrotal swelling showing sheathed microfilariae along with polymorphs, macrophages and eosinophils

Lymph node aspirates showed sheathed microfilariae in the background of mixed population of lymphoid cells comprising of mature lymphocytes, centrocytes, centroblasts, dendritic cells and few eosinophils.

Cytological findings of soft tissue swellings showed microfilariae along with neutrophils, eosinophils and granular debris. Epithelioid granuloma was seen in one case of subcutaneous nodule.

Cell adherence of inflammatory cells and macrophages to microfilariae was seen in three out of 24 cases.

Discussion

Filariasis is a major public health problem in tropical countries, including India. In endemic areas like Eastern part of Uttar Pradesh, people become infected early in life with a peak between 15 to 20 years. A majority of infected individuals in filarial endemic communities were asymptomatic.

In the present study maximum cases (eight out of 24 cases) were reported from breast lumps. These cases presented with breast swelling and pain. Erythema was noticed in two out of eight cases.

Many authors have reported microfilariae in breast lumps by FNAC smears.[2-46-8] Aspirates from lymph nodes (five out of 24), demonstrated microfilariae in a background of reactive lymphoid cells. Similar finding was reported by Joshi et al[12] and Varghese et al.[3]

Four cases of scrotal swellings showed microfilariae. The lymphatic vessels of spermatic cord appear to be common and perhaps the principal site of adult Wuchereria bancrofti in men with asymptomatic microfilaremia. Occurrence of living W bancrofti in scrotal area of men was demonstrated by Noroes et al.[15]

Three cases of thyroid swellings showed microfilariae along with colloid and thyroid follicular cells. Similar findings were also reported by Varghese et al[3] and Yenkeshwar et al.[12]

Two cases of soft tissue swellings and one case of ascitic fluid showed microfilaria along with inflammatory cell including eosinophils, lymphocytes and macrophages. Demonstrations of microfilariae from these sites were also reported by other workers.[2416]

Out of 24 cases showing microfilariae in FNAC smear examination, blood eosinophilia was present in eight cases, of which microfilaremia in nocturnal venous blood smear examination was observed in three cases only. Findings are consistent with observation made by others,[101718] who reported that filariasis can exist without microfilaremia.

Significant adherence of inflammatory cells and macrophages to microfilariae was present in three out of 24 cases. Cell adherence to microfilaria of W. bancrofti was first described by Pandit et al.[19] Cell adherence was also reported by Walter et al.[10] Degenerated microfilaria and coiled larvae were also seen surrounded by inflammatory cells.

Conclusions

Despite high incidence of filariasis, microfilaria in fine needle aspiration cytology is not a very common finding. Careful screening of FNAC smears is helpful in detecting microfilaria even in asymptomatic patients. Undoubtedly the demonstration of parasite, in aspirate, play a significant role in recognition of disease and institution of specific treatment, thus obviate the severe manifestations of lymphatic filariasis.