A rare case of genital myiasis in a woman with genital prolapse and malignancy and review of the literature

Myiasis is a parasitic infestation caused by the larvae of several species. The infestations reduce host physiological functions; destroy host tissues, and causes significant economical losses. It is very rare disease in USA and Europe, seen rarely in tropical and subtropical countries in persons with poor personal hygiene. Diagnosis and treatment are simple. The location of this infestation at genital region is, however, an extremely rare occurrence. The authors present here one case of genital myiasis affecting a village woman with genital prolapse and advanced vaginal malignancy.

Keywords: Maggot infestation, Myiasis, human genitalia, urogenital myiasis

Myiasis is a parasitic infestation caused by the larvae of several species. The infestations reduce host physiological functions; destroy host tissues and causes significant economical losses. It is very rare disease in USA and Europe, seen rarely in tropical and subtropical countries in persons with poor personal hygiene. Diagnosis and treatment are simple. The location of this infestation at genital region is, however, an extremely rare occurrence. The authors present here one case of genital Myiasis affecting a village woman with genital prolapse & advanced vaginal malignancy.

A 55 years of age, multiparous, postmenopausal women, a housewife (occasionally works at paddy field) comes from remote part of Tripura with presenting complaints of foul smelling blood stained discharge from her prolapsed genital organ for last 1 month. She has noticed something coming out of her vagina for last 10 years. The prolapsed mass used to get reduced in size on lying down position earlier. But for the last 4 months, the prolapsed mass fails to get reduced, rather it increased in size. She also experiences difficulties in micturation and defecation in recent times. There are no significant past and family histories.

On examination, she is found to be of moderately built, poorly nourished. Her personal hygiene is poor. General examination of her does not reveal anything significant. Per abdominal examination are normal. There are no significant inguinal lymphadenopathies.

Local examination reveals healthy vulva. There is complete prolapse of uterus and vagina. The external OS of cervix is lying 7 cm outside the intriotus. The cervix is hypertrophied and the external OS is stenosed. The cervix is otherwise normal. There is a large cauliflower growth measuring 10 x 8 cm ² arising from right lateral vaginal wall closed to the bladder. The center of the growth is covered with necrotic tissue and it bleeds on touch. Foul smelling blood stained discharge from the growth is noticed. Numerous maggots (larvae) are seen under the sloughs that invaded the surrounding tissue. The base of the lesion appears to be indurated, and the lesion is encroached to right lateral bladder wall (cystocele). There is a large rectocele and enterocele present. The prolapse is irreducible due to the vaginal growth and tissue edema.

The patient is admitted for investigation and treatment. Her routine hematological examinations reveal moderate anemia, high total leucocytes count, and neutrophilia. Her urine analysis indicates the presence of infection. She is not diabetic and her renal function is normal according to age. Her VDRL test is nonreactive and HIV test is negative. The histopathological evaluation of the biopsy of the vaginal growth proves poorly differentiated squamous cell carcinoma along with acute inflammation. The entomological evaluation of larvae could not be done due to lack of facility. So the final diagnosis is made to be the irreducible procedentia with squamous cell carcinoma of vagina with myiasis.

The patient’s personal hygiene is taken care of during her hospitalization. She is put on high protein diet. She is given broad-spectrum antibiotics, and other symptomatic treatment. The necrotic tissue (sloughs) is cleaned with antiseptic solution. The maggots are extracted from the crater (within the vaginal growth) with the help of instruments. Terpentine oil and ether is used over the lesion as these help to kill the larvae. The procedentia is dressed daily with a glycerin magnesium sulfate solution to reduce the tissue edema and to improve the vascularization.

Opinion is obtained from a oncologist for further management. As the vaginal cancer is advanced and suspected to infiltrate the bladder wall, it is planned for radiotherapy. The patient is lost for recommended treatment and follow-up due to financial constraint.

Review of the literature

Myiasis is a condition resulting from the invasion of tissues or organs of man or animals by the larvae of several species of flies.

There are two forms of myiasis: obligate, in which the maggots feed themselves on living tissues, and facultative type, where the maggots opportunistically take advantage of wounds or degenerative necrotic conditions to incubate their larvae. ^[1] There are three families of flies encountered in myiasis and can be divided into two groups for comparison of host location strategies:

1. Oestride – they areobligate parasites, they deposit their eggs or larvae directly onto the host.
2. Calliphoridae and sacrophagidae – they are obligate parasite and primary facultative parasite, they deposit their eggs or larvae directly onto the host at some
3. predisposing site, such as those caused by wounding, necrosis. ^[2] In general, obligate myiasis of humans is tropical in origin, whereas facultative myiasis can occur anywhere in the world. These parasites can be identified by microscopic examination or developing these larvae to adult flies for entomological classification.

This condition can occur on any exposed part of the body. Sometimes it makes an entry into the internal organs of the body such as intestine, bone etc. Most common type of myiasis is mucocutaneos type. Cutaneous myiasis is most commonly caused by Dermatobia hominis (human botfly involving the diptherous fly larvae). ^[3] Human genital myiasis is usually present with concomitant sexually transmitted diseases and also commonly seen in immunocompromized individuals. ^[4] There is no case of myiasis in prolapsed uterus with vaginal cancer reported in the literature searched in PubMed.

The lack of personal hygiene is the contributing factor for the cause of myiasis, more so with the genital myiasis. Female flies possibly are attracted by the fetid odor, and lay eggs in existing lesions. ^[4] Thereafter, the larvae invade the tissue and feed themselves on living tissues. Larvae usually pupate within 1-2 days and emerge as adult males 6 days later. ^[5]

The distribution of myiasis is worldwide with more cases being reported from tropical, subtropical and warm temperate areas. This condition is mostly unfamiliar in USA and European countries. However, the rapidity of international air travel permits this exotic tropical infestation to present in any region. ^[3]

Myiasis can be confused to many common conditions such as adenopathy, cellulites, skin abscess, insect bites and subcutaneous cysts. ^[6]

The treatment of the lesion is very simple, extract the larvae and wash the affected area with an antiseptic solution. ^[7] Surgical removal sometimes results in damage to the larva with retention of larval fragments in the wound. Multiple surgical techniques have been described in past, but no single standardized technique for surgical extraction of larvae has been adopted.

It is interesting to note that fly larvae, or maggots, can be used to cleanse necrotic debris from a wound. Because they feed on the necrotic tissue of the wound.

Source of Support: None, Conflict of Interest: None