To the Editor: The recent case report 1 and subsequent correspondence 2,3 raise some important issues surrounding the presence of testicular microlithiasis and nontesticular microlithiasis (macrocalcification) in both the pediatric and adult testis. We note the opinion of Harris 2 with regard to the occurrence of macrocalcification as more likely to represent the presence of a “burned-out” tumor rather than the presence of microlithiasis as advocated by Meyer and Gilbertson-Dahdal. 1,3 It seems to us unlikely that testicular microlithiasis is representative of a burned-out tumor as advocated by Meyer and Gilbertson-Dahdal. 1 Unfortunately the description and depiction of intratesticular calcification in many of the older articles they cite would not stand up to modern-day scrutiny; vague sonographic methods and assessment are only too evident (eg, Figure 4 in the article by Grantham et al 4 depicts areas of macrocalcification described as bright echogenic foci), likely a manifestation of the less sophisticated transducers of that period. The histologic characteristics of testicular microlithiasis are very different from those of the necrosis, macrocalcification, and possible tumor cell remnants associated with a burned-out tumor 5 ; testicular microlithiasis clearly shows calcified intratubular bodies on histologic specimens. 6 The sonographic features of testicular microlithiasis as classically described are unique to this entity and are not mimicked by other forms of intratesticular calcification. However, the underlying association of testicular microlithiasis as well as burned-out tumors (manifested by macrocalcification) with intratubular germ cell neoplasia, a precursor of a germ cell tumor, indicates an increased risk of tumor development in both testicular microlithiasis and macrocalcification groups. Hence, testicular microlithiasis is associated with intratubular germ cell neoplasia and with that association an increased risk of developing a tumor. Thus, an area of macrocalcification may represent a burned-out tumor, but the remainder of the testis remains at risk if intratubular germ cell neoplasia is present, and it usually is present. We believe that the finding of testicular microlithiasis in the case of Meyer and Gilbertson-Dahdal 1 is more likely to indicate the simultaneous presence of intratubular germ cell neoplasia and not areas of a burned-out tumor. The finding of testicular microlithiasis is incidental and is a marker of the risk associated with intratubular germ cell neoplasia, with no manifestation in the testis of a focal tumor or macrocalcification to indicate the origin in the testis of the retroperitoneal germ cell tumor: a truly “silent” testis for the presence of the source of the retroperitoneal germ cell tumor. Harris was unable to identify any studies that address the prevalence of macrocalcification. We have addressed the prevalence of all types of calcification on scrotal sonography and related it to the presence of primary testicular tumors in 3447 patients, 7 having earlier described in detail the types of scrotal calcification that may be encountered. 8 Any intratesticular calcification not typical of the description of microlithiasis was termed “nontesticular microlithiasis calcification (macrocalcification),” and this is the type of calcification that may be shown when a burnedout tumor is diagnosed in the presence of an extragonadal germ cell tumor, as indicated by the experience of Harris. 2 The prevalence of testicular microlithiasis in our study population was 2.0% (95% confidence interval [CI], 1.6%– 2.6%), and that of nontesticular microlithiasis calcification was 1.7% (95% CI, 1.3%–2.3%). The association with a metachronous primary germ cell tumor was significant in both types of intratesticular calcification. 7 A small subset of pediatric patients (n = 198) was also analyzed, with the prevalence of testicular microlithiasis recorded as 2.0% (95% CI, 0.6%–5.1%) and that of nontesticular microlithiasis recorded as 0.5% (95% CI, 0.0%–2.8%). Our figures, although not significant in the pediatric group with the small cohort analyzed, warrant further evaluation. A possible scenario would advocate that testicular microlithiasis is present in the pediatric population at the same level as that seen in the adult population, but nontesticular microlithiasis increases in the adult patient. This scenario would support the theory that nontesticular microlithiasis is a manifestation of a burned-out tumor that puts the patient at risk of developing a further germ cell tumor of the testis or is responsible for an existing extra gonadal germ cell tumor. There are scarce data to support this theory; it is time we looked more closely at the prevalence of testicular calcification in the pediatric population. We would agree with Harris 2 that a burned-out tumor is represented by nontesticular microlithiasis macrocalcification, and testicular microlithiasis has associations with germ cell tumors and extragonadal tumors. However, areas of testicular microlithiasis, as classically described on sonography, do not represent tumor involution.
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Dec 14, 2023
Edgar Medel-Martinez + 2
Open Access
