Subcutaneous hydatid cyst 
Case report 
SUBCUTANEOUS HYDATID CYST 
C. Ferreli, M.G. Murtas, A. L. Pinna, M. Pau, N. Aste and P. Biggio 
ABSTRACT 
The authors describe a case of subcutaneous hydatidosis in a 62-year-old woman. The cyst appeared in the right lumbar regi on 
as an elastic nodule of about 3 cm diameter. The overlying skin appeared normal. Histologically in the deep dermis and in the 
subcutis multiple isolated cystic formations of different sizes composed of an intensely PAS positive wall of concentric lamellar 
structure were present. The inner surface showed small nuclei irnmersed in a granulous cytoplasmatic mass. Within this cystic 
cavity daughter cysts and scolices were observed. Thorough examinations failed to reveal involvement of other organs. 
KEYWORDS 
hydatidosis, echinococcus granulosus, extravisceral echinococcus cyst 
INTRODUCTION 
Hydatidosis is in various parts of the world a frequent 
parasite infestation caused by larvae of Echinococcus 
granulosus and, less frequently, Echinococcus multilocularis 
(1). The adult form ofthis cestode lives in the small intestine 
of dogs, its definitive host. With the faeces the eggs of the 
parasite are deposited in the environrnent from where they 
can infest man, the intermediate host, in various ways. The 
most frequently attributed way of infestation is the digestive-
acta dermatovenerologica A.P A. Vol 2, 99, No 3 
portal-hepatic way (2). Other authors have hypothesized 
alternative ways such as: the digestive-haemo-lymphatic, the 
digestive-biliary-hepatic, the haematic-extrahepatic as well 
as the transcutaneous, transmucous and aerogenous (3). 
Consequently, while the !iver and the Jung are the most 
common sites of the disease, other areas are less frequentl y 
involved and cases with only extravisceral infection sites are 
extremely rare (4). 
99 
CASEREPORT 
A 62-year-old woman presented in the right lumbarregion 
a firm, elastic nodule of a diameter of 3 cm, mobile on both, 
surface and deep planes, covered with healthy asymptomatic 
skin. A surgical excision was performed. Macroscopically 
the lesion appeared like a cyst. 
Fig.1: Dijferent sizes of hydatid cysts in the deep dermis (HE 
20x) 
The histological examination showed in the deep dermis 
and in the subcutis multiple isolated cystic formations of 
different sizes embedded in fibrous connective tissue with a 
moderately dense lymphohistiocytic infiltrate (Fig. 1). The 
cysts were characterized by an intensel y PAS positive wall of 
concentric lamellar structures with small nuclei immersed in 
Fig. 2: The dijferent strata of the cyst wall: proligera, 
chitinosa, pericystium (HE 200x) 
100 
a granulous cytoplasmatic mass on its inner surface and 
contained in theircavities daughter cysts and scolices (Fig. 2, 
3).Amoderatelydensegranulomatousreactionwithnumerous 
multinucleated giant cells surrounded the chitinosa, whereas 
in the periphery a lymphocytic infiltrate with eosinophils was 
observed in the context with fibrosis (Fig. 4). 
Fig. 3: Scolex: the hooks inside the scolex a,:e visible. (PAS 
800x) 
Based on this histological features a diagnosis of fertile 
hydatid cyst was made. 
Thorough examinations were carried out to assess the 
involvement of other organs, but revealed negative results. 
At about one year's distance no relapses orhydatid visceral 
involvement were observed. 
Fig. 4: Granulomatous reaction with numerous multi-
nucleatedforeign body giqnt cel/s surrounding the chitinosa 
(HE lOOx). 
acta dermatovenerologica AP.A. \lol 2, 93, No 3 
DISCUSSION 
In our opinion this case should be one of those very rare 
forms of primary extravisceral hydatidosis fromEchinococcus 
granulosus. Considering the surface localisation of the cyst, 
we hypothesize a case of direct infestation. 
Though rare, the likelihood of a primary skin localisation 
ofthe disease, moreover suggests that, especially in regions 
where the disease is endemic, such as ours (5), greater care 
should be taken when exciding a subcutaneous cyst-like 
neoformation lestcarelessmanoeuvres such as partial biopsies 
orneedle biopsies should lead to dissemination of the parasite. 
REFERENCES 
l. Sampietro R, D'urbano C, De Angelis G, Castelli E. 
L'Echinococcosi epatica recidivante. Presentazione di un 
caso e revisione letteratura Min. Chir. 1991; 46: 771-775. 
4. Gharbi H.A, Cheikh M.B, Hamza R, Jeddi M, Hamza B, 
Jeddi H, Bendridi M. F. Les localisations rares de l'hydatidose 
chez l'enfant. Ann. Radiol. 1977; 20(1): 151-157. 
2. Belli L Aseni P, Rondinara G. F, Bertini M. lmproved 
results with pericystectomy in normothermic ischemia for 
hepatic hydatidosis. Sur. Gynecol. Obstet. 1986; 163: 127-
132. 
5. Schintu M, Mudu D, Pinna F, Santus M, Comu A. 
Epidemiologia delle malattie infettive in Sardegna ne! 
decennio 1970-1979. nota II - L'Echinococcosi Rass. Med. 
Sar. 1985; 88: 297-302. 
3. Russo G, Nicoletta G. In tema di localizzazione rare 
dell'echinococco Min. Med. 1974; 65: 3734-3740. 
AUTHORS' ADDRESSES 
Dott. ssa Ferreli Caterina, ricercatore universitario 
Clinica Dermatologica, Universita di Cagliari 
Via Ospedale 46. 09124 Cagliari, Italia 
Dott. ssa Pinna Annaluisa, aiuto corresponsabile ospedaliero, same address 
Dott. ssa Pau Monica, assistente ospedaliero, same address 
Prof. Aste Nicola, professore associato, same address 
Prof. Biggio Pietro, professore ordinario, same address 
Dott. ssa Murtas Maria Grazia, aiuto corresponsabile ospedaliero 
Servizio di Anatomia - Ospedale Oncologico Cagliari. 
acta dermatovenerologica AP A. Vol 2, 93, No 3 JOJ