Multiple pilomatricomas and Steiner disease

ARTICLE

An 18-year-old male adolescent was referred to our department for the presence of multiple skin nodules since the age of 9 years. At the age of 22 months the patient was diagnosed as having myotonic dystrophy (Steinert's disease). So far, nine lesions like these have been excised and histologically analysed, two located on the left arm, one on the neck and one on the scalp. A skin examination revealed three nodular lesions, two localised on the scalp (Fig. 1) and one on the trunk (Fig. 2); the lesions ranged from 0.5 to 3.5 cm, and were hard on palpation and asymptomatic, with elevated, smooth and teleangiectatic borders and a central invagination filled with whitish, firm, granular material.

The lesions were all excised. The histological examination of all the biopsy specimens revealed basophilic cells at the periphery, and islets of shadow cells with an unstained central area at the site of lost nucleus (Fig. 3). The shadow cells were surrounded by a granulomatous infiltration composed mainly of giant cells.

Multiple pilomatricomas and Steiner disease

Diagnosis

All the lesions were diagnosed as pilomatricomas. Pilomatricoma is a rare, asymptomatic tumour originating from hair matrix cells, deeply located in subepidermal tissue, with a nodular aspect and a red-bluish colour [1]. Its typical histopathological findings are viable basaloid cells in the periphery, shadow cells in the central part, as well as calcification foci.

Comment

Prevalence of pilomatricoma in patients with Steinert's disease is greater than in the general population, and pilomatricoma generally presents with multiple lesions [2-3]. Steinert's disease is a neuromuscular, autosomal dominant disease characterized by difficulty in relaxing muscles after contraction. Myotonic Dystrophy Protein Kinase (DMPK) has been recently designated as the gene responsible for myotonic dystrophy [4]: various isoforms of DMPK have been reported in skeletal and cardiac muscles, central nervous tissues, myotendinous tissues and in lymphocytes [5]. The functional role of DMPK has not yet been fully unravelled, although it is thought to play an important role in Ca²⁺ homeostasis and signal transduction [4]. In epidermal cells, calcium influences the behaviour and differentiation: at lower calcium concentrations (0.02-0.01 mM) there is a higher cell proliferation rate but lower terminal differentiation [6]. With electron microscopy (Fig.3) in pilomatricoma immature cortical cells appear in their transitional developmental stage, originating from hair structures, with the more mature cells being transitional cells that have lost their nuclei [7]. Therefore, the difficulty in cell differentiation due to abnormal proteins, as in DM, might explain the higher frequency of pilomatricoma in DM patients than in the general population. Moreover, a rapid onset could be due to the intense proliferation that characterizes hair structures. It might be interesting to investigate on the presence of DMPK in epidermal tissues..

References

1. Delfino M, Monfrecola G, Ayala F, Suppa F, Piccirillo A. Multiple familial pilomatricomas: a cutaneous marker for myotonic dystrophy. Dermatologica 1984; 170: 128-32.

2. Salerni E, Bonatti ML, D'Aurizio C. Multiple pilomatrixomas and myotonic dystrophy: a case report. Riv Neurol 1998; 58: 124-6.

3. Laredo Ortiz C, Munoz Romero F, Mallent Anon J. Multiple pilomatricomas associated with Steinert disease. An Med Interna 1997; 14: 409-11.

4. Ueda H, Ohno S, Kobasyashi T. Myotonic dystrophy protein kinase. Prog Histochem Cytochem 2000; 35: 187-251.

5. Depardon F, Cisneros B, Alonso-Vilatela E, Montanez C. Myotonic dystrophy protein kinase (DMPK) gene expression in lymphocytes of patients with myotonic dystrophy. Arch Med Res 2001; 32: 123-8.

6. Hennings H. Calcium regulation of growth and differentiation of mouse epidermal cells in culture. Cells 1980; 19: 245.

7. Fitzpatrick TB, Eisen AZ, Freedberg IM, Austen KF. Dermatology in general medicine. Fifth Edition. McGraw Hill.

Article accepted on 5/2/02