To the Editor:
We appreciate Dr. Resnik's comments 1,2 and agree with him that melanocytes would be an expected finding in any proliferation of matrical and supramatrical cells based on the physiology of the hair cycle. 3,4 However, missing from this argument that “melanocytic matricoma is simply one expected histologic expression of matricoma” is documented evidence of the clinicopathologic features of non-pigmented (clinically and histologically) matricoma. The original publication of matricoma by Ackerman et al 5 does not describe whether these examples were pigmented clinically nor does it provide any additional clinical information. Furthermore, the silhouette presented by Ackerman et al 5 of matricoma is not identical to that of melanocytic matricoma illustrated in the 3 reports published to date. 4,6,7 Ackerman's figures of matricoma exhibit multiple small, dermal aggregates with cystic, solid and cystic, and solid profiles whereas the profile of melanocytic matricoma is that of a single, solid dermal nodule. Moreover, the appellation of melanocytic matricoma encompasses an entity that, at this point in time, represents a benign, pigmented papule occurring on sun-damaged skin of older individuals formed by a nodular proliferation of neoplastic matrical and supramatrical cells admixed with an apparently normal and numerous population of melanin-laden dendritic melanocytes. 4 Two recent reports bear witness to this clinicopathologic correlation. 6,7 To resolve this question of whether melanocytic matricoma represents a bone fide entity or is simply a variant of matricoma, a comparison of clinical and pathologic features of clinically pigmented (melanocytic matricoma) and non-pigmented matricomas would have to be made examining for significant differences particularly with respect to natural history. At this point, the data does not exist to support Dr. Resnik's hypothesis. We look forward to learning more about matrical proliferations as further case reports and series are published. In time, this issue will be resolved.
J. Andrew Carlson, MD, FRCPC
Andrzej Slominski, MD, PhD
Martin C. Mihm, Jr., MD
1. Resnik KS, Rizzardi C, Melato M. Is melanocytic matricoma a bona fide entity or is it just one type of matricoma? Am J Dermatopathol. 2003; 25:166–167.
2. Resnik KS. Melanocytic matricoma is simply one expected expression of matricoma. Am J Dermatopathol. 2003; 25:(in press).
3. Slominski A, Paus R. Melanogenesis is coupled to murine anagen: toward new concepts for the role of melanocytes and the regulation of melanogenesis in hair growth. J Invest Dermatol. 1993; 101(Suppl 1):90S–97S.
4. Carlson JA, Healy K, Slominski A, et al. Melanocytic matricoma: a report of two cases of a new entity. Am J Dermatopathol. 1999; 21:344–349.
5. Ackerman AB, DeViragh PA, Chongchitnant N. Pilomatricoma and Matricoma. In:Neoplasms with Follicular Differentiation.
Philadelphia: Lea & Febiger;1993:477–506.
6. Rizzardi C, Brollo A, Colonna A, et al. A tumor with composite pilo-folliculosebaceous differentiation harboring a recently described new entity—melanocytic matricoma. Am J Dermatopathol. 2002; 24:493–497.
7. Williams CM, Bozner P, Oliveri CV, et al. Melanocytic matricoma: case confirmation of a recently described entity. J Cutan Pathol. 2003; 30:275–278.