Surgical Science, 2011, 2, 13-15
doi:10.4236/ss.2011.21004 Published Online January 2011 (http://www.SciRP.org/journal/ss)
Plantar Cornu Cutaneum Associated with Cutaneous
Myxoma
Olugbenga Ojo Oludiran1, Victor James Ekanem2, Phillip Felix Umebese3
1,3Department of Orthopaedics and Traumatology
2Department of Morbid Anatomy
College of Medical Sciences, University of Benin, Benin, Nigeria
Received June 1, 2010; revised September 30, 2010; accepted October 10, 2010
Abstract
Cutaneous horns are rare in black patients probably as a result of the rarity of sun induced associated skin
lesions. However reports of these lesions are filtering in from Africa. In this paper we report an unusual case
on the sole of the foot in a native African from Nigeria. This is probably the first documentation of the lesion
on the sole of the foot in the world literature.
Keywords: Horn, Cutaneous Horn, Cornu Cutaneum
1. Introduction
Cutaneous horns or cornu cutaneum as they are some-
times called have been object of curiosity both to the
medical and lay world. The name derives from the re-
semblance to animal horns from which it differs in not
having a bony core [1,2]. From the earliest documented
case in 1588 there have been several cases reported.
However most of the reports were in the light skinned
races because of its association with sun exposure and
actinic keratoses. Over 30% of cases are seen in the head
and neck region [3]. There have been reports on occur-
rence in unusual locations such as the lacrimal sac [2],
nasal vestibule [4], glans penis [5-7] and the lower lip [8].
Little attention has been paid to this morphologic entity
in the African races with a report [3] from East Africa in
2007 appearing as probably the first. This occurred on
the scalp following chronic burn scarring. An earlier re-
port on this condition from Sudan was in an Arab [3].
This report is presented to document the first case in a
Nigerian woman occurring in the sole of the foot.
2. Case History
A 54 year old Nigerian woman presented to the Plastic
Surgery clinic of the University of Benin Teaching Hos-
pital, Benin City, with a recurrent painful growth on the
sole of the left foot of three years duration. The pain
predated the growth by two weeks, was intermittent,
worse with walking barefooted and relieved with hot
compresses. The growth was hard and progressively in-
creased in size in spite of antibiotic medicatio ns. She had
a surgical excision a year later at the Military Hosp ital in
Benin but had a recurrence within a few weeks. She had
no diagnosed premorbid condition. She had no known
allergy and neither smoked nor used alcohol. On exami-
nation, She was an otherwise healthy looking woman
who was not pale. Her cardiovascular system was normal
with BP 120/80. Sh e had a horny growth 40 mm long on
the sole of the hind foot the shape of a twisted cone de-
viating medially. The diameter at the base was 30
mm(Figure 1). It was not tender and the surrounding
skin appeared normal. The sensation in the surrounding
skin was normal (touch and pin prick), and peripheral
circulation was adequate. Regional nodes were not en-
larged. A gross clinical assessment of a cutaneous horn
was made and she was scheduled for an excision biopsy.
Her preoperative hematocrit was 9.7 g/dl and blood sugar
was normal. She had surgical excision with 2 cm rim of
normal skin at the margins under local anaesthesia. The
growth was entirely cutaneous, not extending into the
subcutaneous tissue. The surgical defect was resurfaced
with a full thickness skin graft from the groin retained
with a bolus dressing. The post operative course was
uneventful with satisfactory wound healing (Figure 2).
She was discharged on the 10th postoperative day and has
been followed up in the outpatient clinic.
Histology showed markedly hyperkeratotic and acan-
thotic epidermis with prominent rete pegs. Beneath the
epidermis is prominent mucinous matrix in which there

O.O.OLUDIRAN ET AL. 14
Figure 1. Cutaneous horn on the sole of the foot.
Figure 2. The same foot after excision and full thickness
skin grafting.
are variably shaped fibroblasts, thin collagen bundles and
thin capillaries (Figure 3 and 4).
3. Discussion
Reported cutaneous horns appear uncommon in the black
races but are by no means unheard of. The corresponding
author recalls childhood folklore often told, of a certain
“Alade” who grew a horn on his head. It is however un-
known whether that was real or just a myth. Poor utiliza-
tion of orthodox medical facility, inadequate documenta-
tion and lack of reporting are issues that contribute to the
perception of rarity of certain medical entities in our
population. With increasing urbanization and improved
medical record keeping increasing number of hitherto
conceived rare conditions will be reported.
Cutaneous horns have been described in many parts of
the body [1-8]. A search of the literatu re however would
suggest this to be the first from the sole of the foot. Al-
though sun exposure has been touted to be the major risk
factor, this would not appe ar to be the cause in this case.
Chronic irritation as occurs from the repeated trauma of
walking bare footed could be responsible. This is similar
to the clinical history of malignant melanoma which is
more common on the sole of the foot in our population.
Although the aetiology is not very clear, its morbid
anatomy has been well described. It consists essentially
of dead cornified cutaneous excrescence organized in the
shape of a horn displaying hyperkeratosis, acanthosis,
Figure 3. Histological section of the cutaneous horn showing
prominent rete pegs, thin collagen bundles and fibroblast
within the mucinous matrix.
Figure 4. A section of the cutaneous horn showing hyperk-
eratosis, acanthosis and myxoid stroma.

O.O.OLUDIRAN ET AL. 15
dyskeratosis, papillomatosis and inflammatory infiltra-
tion of adjacent dermis [1,5]. These may be superim-
posed on pathologic features of an underlying associated
disease.
Cutaneous horns have been associated with a wide va-
riety of clinical conditions, benign, premalignant and
malignant. These include actinic keratosis, seborrheic
keratosis, keratoacanthoma, haemangioma, keratotic
pseudopapillomatous balanitis, sebaceous adenoma, ver-
ruca vulgaris, trichilemma, histiocytoma, molluscum
contagiosum, grannular cell tumour, Bowen’s disease,
Paget’s disease of the breast, basal cell carcinoma
squamous cell carcinoma, malignant melanoma and Ka-
posi sarcoma [1,10,11]. It has also been associated with
cutaneous spread of malignancies as was reported by
Rajeev and colleagues in association with renal cell car-
cinoma [8]. In our patient the cutaneous horn is associ-
ated with a myxoma. Thus it is essential to look beyond
the horn in planning the management. Large size, rapid
growth and tenderness at the base have been associated
with malignancy [1,5]. In this case, a wide excision with
a 2 cm margin was carried out for adequate oncological
clearance in case of possible malignancy. The specimen
was evaluated histologically for pathological diagnosis
and microscopic evaluation of the margin of resection.
Other treatment options include excision and direct
wound closure where feasible, electrocautery, cryosur-
gery, and laser ablation of the base after removal of the
horn [12]. Recurrence following a previous excision, at
another centre, in this patient is probably from in-
adeqaute excision. However recurrences like this has
been noted to occur. This report documents, perhaps for
the first time, a cutaneous horn on the sole of the foo t of
a black African.
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