Case 192. Sparganosis (40 y-o F)
    Biopsy from creeping disease (cutaneous larva migrans) of the abdominal skin, seen after eating meat of wild chicken    
Key words : 
Sparganum mansoni, creeping disease, larva migrans, plerocercoid    
The white plerocercoid seen in the subcutaneous tissue along the excision line (gross findings). Moving speed of the larva, Sparganum mansoni, is slow, so that the larva can easily be found during biopsy procedure.   Cut surfaces of plerocercoid located in the dermis and subcutaneous tissue. Folded tegument is seen (HE, low power). The formation of lymphoid tissue and granuloma represents a slow moving speed of the larva.
Tunnel-like tissue defects (dead spaces) filled with inflammatory exudates represent a trail of plerocercoid movement (HE, low power). Eosinophilic reaction is mild.   The larva histologically consists of the microvillous tegument, subtegumental spindle cell layer and internal myxoid matrix (HE). Neither gut nor gonad is seen. In contrast to cysticercosis, no protoscolex is found.
In the myxoid matrix of the plerocercoid body, excretory vesicles, muscular fascicles and calcified bodies are seen (HE, high power). The calcified bodies are the hallmark of the Cestoda (tapeworm).   Kossa stain clearly discloses the calcified bodies. The first intermediate host of Sparganum erinacei is Cyclops, and the second intermediate hosts are commonly the snakes, frogs and wild chickens.
The matrix is rich in glycogen (PAS). The tegument is also PAS-reactive. The non-segmented plerocercoid survives for years, to grow up as large as 60 cm.