Ds. Raso et al., CATERPILLAR BODIES OF PORPHYRIA-CUTANEA-TARDA ULTRASTRUCTURALLY REPRESENT A UNIQUE ARRANGEMENT OF COLLOID AND BASEMENT-MEMBRANE BODIES, The American journal of dermatopathology, 18(1), 1996, pp. 24-29
Caterpillar bodies are eosinophilic, periodic acid-Schiff (PAS)-positi
ve globules arranged in a linear fashion in the epidermis overlying su
bepidermal blisters of porphyria cutanea tarda (Am J Dermatopathol 199
3;15:199-202). We retrospectively studied by transmission electron mic
roscopy nine cases of porphyria cutanea tarda (PCT) that demonstrated
caterpillar bodies. We identified three components of the eosinophilic
bodies: degenerating keratinocytes, colloid bodies, and basement memb
rane bodies. The colloid bodies consisted of whorled masses of filamen
ts containing degenerating melanosomes, vacuoles, mitochondria, and de
smosomes. Basement membrane bodies were composed of convoluted basemen
t membrane material and associated collagen. Both colloid and basement
membrane bodies were often associated with degenerating keratinocytes
, were located both intra and extracellularly, and were occasionally f
used to one another. We believe that caterpillar bodies are a combinat
ion of degenerating keratinocytes, colloid bodies, and basement membra
ne bodies formed by repeated blistering and reepithelialization with t
ransepidermal migration. Furthermore, we believe that caterpillar bodi
es are a diagnostic clue for the diagnosis of PCT.