ARTICLE
Auteur(s) :, Gonca Boztepe1,*,
Mohammad Rakhshanfar1, Gül Erkin1, Özay
Özkaya2, Sedef Şahin1
1Hacettepe University Faculty of Medicine, Department
of Dermatology Sihhiye, 06100, Ankara, Turkey Fax: (+90) 312 309
7265.
2Hacettepe University, Faculty of Medicine, Department
of Pathology, Sihhiye, 06100, Ankara, Turkey
accepté le 5 Avril 2004
Cutaneous silica granuloma (CSG) is a poorly understood, rare
condition that is occasionally encountered after trauma. It was
first described by Shattock in 1916, when he performed a biopsy on
a lip tumor that has arisen in a scar resulting from an injury that
had happened 11 years previously [1]. Since then, relatively few
additional cases have been reported.Most patients with CSG lack
clear-cut histories of traumatic exposure [2]. Even if they recall
an injury, the characteristic latency period until the onset of
granuloma challenges the diagnosis [3].It is usually presented
clinically as erythematous, firm, non-tender, dermal or
subcutaneous nodules. Non-caseating granulomatous infiltration with
lymphocytes, histiocytes, and giant cells constitute the
histopathologic picture of CSG, which might easily be
misinterpreted as sarcoidosis or cutaneous leishmaniasis unless
such specimens are routinely examined under polarized light
microscope [4]. Birefringent particles visualized under polarized
light microscope lead to a proper diagnosis of CSG, which may
further be confirmed by energy-dispersive X-ray analysis. Here we
describe a patient with characteristic clinical and microscopic
findings of CSG.
Case
A 38-year-old male patient presented with a 1-year history of a
pruritic nodular lesion on the left forearm, which had been
gradually enlarging in size. The patient’s past history was
unremarkable except that he had been working at a glass factory
until 4 years previously. He did not recall any injury to the
forearm during the time he worked in the factory.
Examination of the skin revealed a 1.5 × 1.5 cm firm,
erythematous, non-tender nodule with a pearly and telangiectatic
surface on the left forearm ( (figure 1) ). No palpable
regional lymphadenopathy was noted. A skin punch biopsy
demonstrated diffuse granulomatous infiltration involving the whole
dermis with abundant giant cells and sparse lymphocytes ( (figure 2) ).
Refractile particles were visualized within these giant cells (
(figure 3) ).
These particles were birefringent under polarized light. The lesion
was then totally excised. This resulted in total resolution without
recurrence.
Discussion
Silica granuloma occurs after the introduction of silicon dioxide
(silica) into the skin, usually after an injury. Silica is one of
the most abundant elements in the earth’s crust. It is present in
sand, glass, granite, mica, cement, brick and asbestos. The most
common form of silica is quartz, which is a constituent of nearly
every rock. There is often a characteristic latency period between
the time of silica exposure and the time of clinical onset of
granuloma. This has ranged from less than 1 year to more than 50
years with a mean interval of approximately 10 years, in published
records [2]. Besides, most recorded instances of silica granuloma
do not present clear-cut histories of trauma.
Single or multiple erythematous, firm, non-tender, dermal or
subcutaneous nodules are the most common clinical presentation of
silica granulomas [5]. There have also been reports accompanied by
regional lymphadenopathy, with silica present in the lymph nodes on
histological examination [6, 7].
Biopsy specimens characteristically demonstrate a histological
picture of a foreign body granuloma with abundant giant cells
surrounding numerous crystalline structures. Cases of more
organized non-caseating epitheloid granulomas may look extremely
like cutaneous sarcoidosis [2, 4]. Polarized light microscopy is
essential for a proper differential diagnosis of silica granuloma
and sarcoidosis. The diagnosis of silica granuloma can further be
confirmed by energy-dispersive X-ray analysis [2, 8].
The pathogenesis of silica granuloma is poorly understood.
According to one of the two most supported theories, silica in the
tissue is hydrolyzed by the interstitial fluids to a colloidal
state which after many years triggers a granulomatous response [9].
The second theory is based on the idea that silica granulomas
represent a delayed type of hypersensitivity [5].
Surgical excision appears to be the treatment of choice for
silica granuloma [8]. Alternative treatments include intralesional
steroid injections [4], systemic steroids, irradiation, and
antibiotics. However, reports of spontaneous resolution of silica
granuloma somehow obscure the effectiveness of these therapies. It
is mentioned in the literature that if spontaneous resolution is to
be observed, it occurs between 1 to 12 months [8].
In our case, despite negative history of an injury to forearm,
exposure to silica at the glass factory, the presence of latency
period and classical clinical as well as microscopic features were
the clues that had led to the diagnosis.
Concerning silica granuloma, the questions of why it is so
rarely seen despite its ubiquitous nature in the environment, and
what are the roles of clinical underdiagnosis and spontaneous
resolution on its rarity, are yet to be elucidated.
References
1 Shattock SG. Pseudotuberculoma silicotum of the lip. Proc R
Soc Med 1916; 10: 19-21.
2 Mowry RG, Sams M, Caulfield JB. Cutaneous
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cases with review of the literature. Arch Dermatol 1991; 127:
692-4.
3 Finley J, Knabb J. Cutaneous silica granuloma. Plast
Reconstr Surg 1982; 69: 340-3.
4 Kaya TI, Kokturk A, Polat A, Anadolu R,
Tursen U, Ikizoglu G. Cutaneous silica granuloma in a
child. Pediatr Dermatol 2003; 20: 40-3.
5 Rank BK, Hicks JD, Lovie M. Pseudotuberculoma
granulosum silicoticum. Br J Plast Surg 1972; 25: 42-8.
6 Kuchemann K, Holm R. Unusual silica granulomas of
skin with masssive involvement of axillary lymph nodes. Pathol Res
Pract 1979; 164: 198-206.
7 Morgan RJ. Cutaneous silica granuloma. Cutis 1986; 38:
95.
8 Bovenmyer DA, Landas SK, Bovenmyer JA.
Spontaneous resolution of silica granuloma. J Am Acad Dermatol
1990; 23: 322-4.
9 Shelley WB, Hurley HJ. The pathogenesis of silica
granulomas in man: a non-allergic colloidal phenomenon. J Invest
Dermatol 1960; 34: 107-22.
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