Does cutaneous silica granuloma develop mainly in predisposed patients?

ARTICLE

Auteur(s) : Angel FERNANDEZ-FLORES¹, Manuel G. MONTERO²

¹ Histopathology Dept, Clinica Ponferrada, Leon, Spain
² Dermatology Dept, Clinica Ponferrada, Leon, Spain
<gpyauflowerlion@terra.es>

We have read with great interest the report about silica granulomas [1], and agree with the authors, who wonder why these lesions are not more common in daily practice, in view of the ubiquity of silica.
We also recently saw a case in which no history of exposure to silica could be recorded, and which was interesting because of its association with a long history of sarcoidosis, since both entities have been previously related in literature [2-7].
Our patient, a 52-year-old woman, had been diagnosed with a systemic stage I-sarcoidosis twelve years previously, and was currently stable with normal clinical parameters.
She went to the Dermatologist, presenting non-tender red and pearly patches, plaques and nodules, which had appeared on her knees and elbows, two years before. The biggest lesion was 7 mm in diameter (figure 1A). Some of the lesions spontaneously regressed. There was no history of traumatism, injury or professional exposure to silica.
The biopsy of one of the lesions, from an elbow, showed a typical sarcoidal granulomatous dermatitis (figure 1B), with refractive particles in the center of the granulomas (figure 1C). No asteroid or Schaumann bodies were found.
The histochemical study with Giemsa, Ziehl-Neelsen and PAS failed to show any micro-organisms.
The reason why silica granulomas are not seen more often in daily practice could be due to their underdiagnosed condition [8], or to spontaneous resolution. But another possibility is that a susceptibility to form granulomas, in the patient, is necessary for these to appear.
In the literature, there is not always a clear relationship between sarcoidosis and silica granuloma, a subject complicated by the use of the term scar-sarcoidosis to refer to granulomas appearing in old scars [4].
Silica particles were a mere contaminant for some [5], but were considered as a diagnostic clue by many, excluding a sarcoidosis when present [4, 5, 8].
Several studies have shown how foreign bodies are not an uncommon finding in cutaneous granuloma of patients with systemic sarcoidosis [7,8]. This might be due to a tendency to easily develop granulomas in these patients, either against foreign bodies [7], or scars.
In conclusion, the term scar-sarcoidosis should only be used, if ever, when a systemic sarcoidosis is present; and siliceous particles in a granuloma cannot exclude cutaneous sarcoidosis. n

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5. Walsh NM, Hanly JG, Tremaine R, Murray S. Cutaneous sarcoidosis and foreign bodies. Am J Dermatopathol 1993; 15: 203-7.

6. Marcoval J, Mana J, Moreno A, Gallego I, Fortuno Y, Peyri J. Foreign bodies in granulomatous cutaneous lesions of patients with systemic sarcoidosis. Arch Dermatol 2001; 137: 427-30.

7. Val-Bernal JF, Sanchez-Quevedo MC, Corral J, Campos A. Cutaneous sarcoidosis and foreign bodies: an electron probe roentgenographic microanalytic study. Arch Pathol Lab Med 1995; 119: 471-4.

8. Mowry RG, Sams WM Jr, Caulfield JB. Cutaneous silica granuloma; a rare entity or rarely diagnosed?: report of two cases with review of the literature. Arch Dermatol 1991; 127: 692-4.