Unusual Intra-Abdominal Encapsulated Foreign Body in a Wild Female King Eider (Somateria spectabilis)
During June 1999, 12 adult king eiders (Somateria spectabilis) were captured and transported
to a field surgical site in Prudhoe Bay, Alaska. Ventral midline laparotomy was performed under isoflurane anesthesia
(Aerrane, Fort Dodge Animal Health, Fort Dodge, IA 50501 USA) for satellite transmitter implantation on these birds.
Incision into one of the females revealed the presence of a slightly irregular oval mass that was loosely adhered to
adipose and fibrous tissue within the caudal right mid-abdomen. The mass was bluntly dissected free revealing no distinct
connection to any vessels or abdominal organs. The abdominal incision was closed in two layers, the linea alba and then
skin using 3-0 braided absorbable suture on a cutting needle (Vicryl, Ethicon, Inc., Somerville, NJ 08876 USA) in a simple
continuous pattern in each layer. Recovery from anesthesia was uneventful.
The mass measured 4.2 cm x 3.1 cm x 2.3 cm and weighed 30 g. Incision into the mass revealed a thin
fibrous capsule surrounding a large concreted mass of smooth round rocks imbedded into a dense dry "chocolate" brown
matrix. Aerobic culture of the internal concretion demonstrated no growth after 48 hr. Histopathologic examination of the
membrane showed only a well organized foreign body reaction with an inner layer of amorphous eosinophilic debris. A layer
of epithelioid macrophages and multinucleated giant cells, then a layer of fibrous tissue and scattered aggregates of
lymphocytes and plasma cells, formed the outer surface. Within the inner debris and also in pockets within the wall were
small numbers of bacteria and accumulations of globular to spiculated, brightly refractile yellow or golden material that
could be bile or another pigmented material.
The mass appeared to represent the end result of a chronic inflammatory process. The condition may
have resulted from aspiration of rocks that settled into the abdominal air sac but the size of the individual stones seems
to make this route unlikely. An alternate source could be impaction of a gastrointestinal diverticulum or gallbladder
which became strangulated, walled off, and separated from the original structure. There was no evidence of abdominal wall
trauma or external injury.
The female was in good breeding condition, weighing 1720 g and showed no other physical or behavioral
abnormalities. This animal had been captured with its mate in modified mist nets as they flew onto a recently melted
freshwater pond. Both birds were banded but excluded from the tracking study and released at the capture site without