|Year : 2021 | Volume
| Issue : 1 | Page : 49-52
Sparganosis mimicking a soft-tissue tumor: A diagnostic challenge
Shiwangi Sharma1, Rakesh Kumar Mahajan1, Hira Ram2, M Karikalan3, Arvind Achra1
1 Department of Microbiology, ABVIMS, Dr. RML Hospital, New Delhi, India
2 Division of Parasitology, ICAR-IVRI, Bareilly, Uttar Pradesh, India
3 Centre for Wildlife Conservation Management and Disease Surveillance, Indian Veterinary Research Institute, Bareilly, Uttar Pradesh, India
|Date of Submission||11-Apr-2020|
|Date of Acceptance||17-Jun-2020|
|Date of Web Publication||13-May-2021|
Rakesh Kumar Mahajan
ABVIMS, Dr. RML Hospital, New Delhi - 110 001
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Human sparganosis is a rare but important food borne zoonosis and could be attributed to increased consumption of raw meat of fish, frogs, snakes etc. Sparganosis may involve varied organ systems but subcutaneous sparganosis remains the one of the commonly reported clinical condition. Rarity of this problem reinforces the necessity of sensitising the treating physicians of the differential possibility of this infection in patients with history of practice of consuming raw meat. Expansion of health communication and provision of safe food and water by the civic agencies can be a part of powerful preventive strategies.
Keywords: Human sparganosis, subcutaneous sparganosis, zoonotic parasitic infections
|How to cite this article:|
Sharma S, Mahajan RK, Ram H, Karikalan M, Achra A. Sparganosis mimicking a soft-tissue tumor: A diagnostic challenge. Trop Parasitol 2021;11:49-52
| Introduction|| |
Sparganosis is a parasitic human illness caused by the plerocercoid larva (sparganum) of species of Spirometra, a pseudophyllidean cestode. Sparganosis is a rare disease as only about 450 cases have been described, mostly from Japan, China, Korea, and Southeast Asia. The genus Spirometra has global distribution, although most human cases of sparganosis have been reported from Southeast Asian countries. In India, sporadic cases are being reported from various regions of the country and may emerge as a concern of significant public health importance. As this infection is rare, the treating physician with little or no experience of this larval condition may not entertain the possibility of sparganosis in the differential diagnosis. Here, we report a case of subcutaneous sparganosis in the right foot of a young girl who was also diagnosed as a case of soft-tissue tumor till a pair of thin, long, white-colored parasites was seen in the lesion after an incision was made and diagnosis was revised to a parasitic insult.
| Case Report|| |
A young girl, 4 years of age, resident of Delhi, presented to the orthopedic outpatient department with complaint of pain and swelling of 10 days in the right foot. On examination, a swelling was observed on the dorsum of foot over the 2nd, 3rd, and 4th metatarsal region, measuring 3 cm × 2 cm. The swelling was tender and fluctuant with no other signs of inflammation. The parents gave a history of blunt injury over the same site 2–3 months back. X-ray foot was suggestive of soft-tissue injury with no bony involvement. Routine hematological (no eosinophilia) and biochemical parameters were within reference ranges. There was no eosinophilia. On the basis of clinical history, a diagnosis of soft-tissue injury post blunt trauma was considered and to immobilize the foot, a slab was fixed. When there was no relief to the original presenting features of pain and swelling after 1 week, the slab was removed, and a diagnosis of soft-tissue tumor was contemplated. Before taking the child for surgery, fine-needle aspiration cytology (FNAC) and magnetic resonance imaging (MRI) of the suspected site were advised for further workup on the case. FNAC findings reported hemorrhagic smears with occasional polymorphs and few histiocytes and debris, suggestive of inflammatory swelling. On MRI, short TI inversion recovery hyperintense signal was noted in the head and body of the metatarsal associated with significant surrounding myofascial edema [Figure 1]. The MRI findings hinted toward an infective etiology rather than of traumatic antecedence. A clinical decision to surgically explore the swelling was undertaken. At the time of surgery, the nick given over the swelling, expressed clear jelly-like fluid. On extending the incision, two long, coiled, ivory-colored, nonmotile parasites were discovered [Figure 2]. The parasites were extracted, and the lesion was sutured after the saline toileting. On examination, the parasites were ivory in color with uneven thickening [Figure 3]. One of the parasites was about 10 and the other was 8 cm long and their average width was about 1.2–1.5 mm. The posterior end was tapering [Figure 4], measuring approximately 0.6 mm, and the anterior end looked comparatively incomplete. Only one parasite was submitted to the department of microbiology for identification. Because the parasite did not match with any of the usually encountered worms and appeared to signal toward some larval stage of the worm, it was decided to send the parasite to the Indian Veterinary Research Institute (IVRI), Izatnagar, Uttar Pradesh, for further examination and final identification. It was communicated by the IVRI that the specimen forwarded was in all probability sparganum of spirometra because no cuticle was seen in any of the histological sections examined, but the outer wall greatly resembled with tegument of the plerocercoid larva [Figure 5]. It was also reported that although the anterior end was damaged, the morphological details and histology of the specimen submitted confirmed and compared well to the probability of sparganum of Spirometra spp.
|Figure 1: Magnetic resonance imaging foot: Hyperintense signal noted around the 2nd metatarsal|
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|Figure 5: Hematoxylin and eosin stain: Cut section showing the absence of cuticle|
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The patient was not prescribed any antiparasitic drugs and discharged with a course of antibiotics. The child was taken for regular follow-up, and the postoperative period was uneventful till 6 months after the surgery.
| Discussion|| |
Sparganosis has been reported worldwide, especially in East Asia (China, Japan, and Korea), South-east Asia (Malaysia, India, and the Philippines), and South-west USA. The life cycle of this parasite is complicated and requires three different hosts. Adult members of the genus Spirometra live in the intestines of canine or feline hosts (the definite hosts). Eggs are shed in their feces and embryonate in the environment and release coracidia in water, which are ingested by copepods (fresh water crustaceans such as Cyclops), the first intermediate hosts and develop into procercoid stage. The procercoid larvae develop into plerocercoid larvae in the second intermediate host (fish, reptiles, and amphibians) after they ingest infected copepods and acquire procercoid larvae. The cycle is completed when a predator (dog or cat) eats an infected second intermediate host. Humans primarily serve as paratenic or an intermediate host and are infected with the larval stage of the worm (sparganum). In exceedingly rare cases, the sparganum might develop into an adult worm in the human intestine. Humans acquire sparganosis by drinking water contaminated with infected copepods, consuming the flesh of an undercooked second intermediate, or application over wounds of poultices that use raw skin of infected poikilothermic intermediate hosts. The incubation period ranges from 20 days to 14 months, although spargana can live up to 20 years in a human host.
The migration of the plerocercoid larva to the subcutaneous tissue is usually painless and was experimentally demonstrated by Mueller and Coulston after self-inoculating themselves with the larvae. Sparganosis of subcutaneous tissue has been described as the most common clinical presentation in studies from various countries though migrating spargana may locate into diverse sites such as breast, orbit, urinary tract, pleural cavity, lungs, abdominal viscera, and the central nervous system and can cause varied presentations depending on the final location. However, in few cases, the patient may not complain of any symptom at all or just nonspecific discomfort, pain, or a palpable mass. In 2018, Kim et al. in their retrospective review of about 90 years have reported cases of subcutaneous sparganosis in patients mainly in their sixth decade, though two children of 4 and 6 years of age were also found to be affected with subcutaneous sparganosis. The child in this case was also just 4 years old, belonged to a low socioeconomic stratum, and had significant history of consuming partially or uncooked fish. In addition, the mother of the child informed using unboiled water for drinking. In this particular case, the source of infection appears to be food borne, and it is hypothesized that the migrating larva might have been stuck amidst the capillary reaction after the blunt trauma of the foot. The parasites developed and matured locally, causing a soft tissue-like swelling. It also requires underscoring that there was no eosinophilia and no signal suggestive of parasitic etiology in the MRI scan. Human sparganosis has been addressed as a surgical disease that depends entirely on the detection of larvae in the lesions. Surgical excision is considered and remains a cornerstone of the treatment because there is no evidence of proven usefulness of medical treatment though praziquantel has also been used with limited success.,
Due to the rarity and the varied presentation of the disease, sparganosis remains a diagnostic challenge. Awareness regarding the disease is needed among the medical fraternity. Furthermore, public health strategies need to focus on providing clean water, especially in areas with ponds or ditches. This will help in plummeting the potential habitats for infected copepods and downsizing and checking the problem of sparganosis.
| Conclusions|| |
In India, sparganosis appears to be an important food-borne zoonosis associated with drinking of contaminated water or consumption of infected raw or undercooked meat, but there could be underreporting of these cases because it may not be possible to accurately quantify the problem on account of lack of adequate knowledge of its existence in the medical fraternity, leading to misdiagnosis of this parasitic condition. Although extraction of the parasite remains the mainstay of diagnosis, all the suspected cases need to be carefully screened for surrogate markers such as absolute eosinophil counts. It may also be scientifically highly prudent if populations from high-risk areas are surveyed by a robust well-validated serological testing such as sparganosis immunoglobulin ELISA to have some idea about the magnitude of the problem. Needless to say that expansion and strengthening of public health interventions in areas of safe food and drinking water would be integral to control strategies of this parasitic larval zoonosis.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]