Discussion:
Omphalolith or umbilical concretion is a rare and benign affection due
to the accumulation of sebum and keratin in the umbilicus (2,3). It
usually presents as a firm black mass. The pigmented color of the
majority of omphaloliths is explained by melanin accumulation and lipid
oxidation (4).
Omphalolith mainly affects elderly women with deep and narrow umbilicus
and poor corporal hygiene (5). Obesity is another predisposing factor
(5,6). In the first case, a deep and retracted umbilicus associated with
insufficient hygiene led to the formation of the omphalolith in a young
and non-obese female patient. Having Wilson’s disease with neurological
symptoms and being dependent on her mother may explain insufficient
hygiene in this case. In the second case, a narrow and deep umbilicus
associated with obesity predisposed to omphalolith.
Omphalolith usually remains asymptomatic for several years. I can be
noticed by chance or after secondary complications (3). Repetitive
trauma can cause irritation, erosions, bleeding, and pyogenic granuloma.
Secondary infection, abscess formation, cellulite, or even peritonitis
can also be the revealing symptoms of this condition (3,4,6) .
The diagnosis of omphalolith is based on clinical examination.
Dermoscopy shows aggregates of pigmented keratin. If a histopathological
examination is performed, it reveals laminated keratin associated with
amorphous sebaceous material.
Differential diagnoses include malignant tumors comprising Mary Joseph’s
nodule and malignant melanoma. Benign affections can mimic umbilical
concretion such as keloids, umbilical endometriosis, dermatofibroma, and
persistent omphalomesenteric duct (1,2,6). Therefore, early recognition
of omphalolith is important to prevent unnecessary investigations.
The treatment consists of a gentle extraction of the calculus using
forceps (5,6). In our cases, it allowed the extraction of the entire
mass with no bleeding. Excision of an associated pyogenic granuloma can
be necessary in some cases. Patients’ education on proper corporeal
hygiene is paramount to prevent recurrences (3,4,6). The excision of
the umbilicus may be recommended in some recalcitrant cases(1).