SESSIONE: Dermatologia Oncologica

I tumori di Spitz: problematiche concettuali e pratiche
G. Ferrara

Melanocytic lesions described by Sophie Spitz in 1948 were first considered as representing a juvenile variant of malignant melanoma, because they showed an atypical histological appearance and occurred in children and in young individuals. Subsequently, such lesions were regarded as constituting an atypical variant of nevus, because they appeared to show a clinical benign behavior. Also, they were considered as insidious simulators of malignancy, because histologically they strongly resembled melanoma. Later, some lesions displaying the histological characteristics of such tumors were considered to be malignant, because patients have showed lymph node metastases. Consequently, it was hypothesized a histological spectrum of lesions, including benign, atypical and malignant forms, whose relative borders were ill defined. However, the existence of such a spectrum was denied, considering Spitz lesions as nevi, only pseudomalignant lesions, biologically unrelated to malignancy and to malignant melanoma. Moreover, the diagnosis of such lesions may be extremely difficult, even among experts.

Probably, only new future techniques will solve these problems. However, an analysis of facts may suggest that Spitz lesions have been and still are regarded in an incorrect perspective. Certainly Spitz lesions are enigmatic, but, perhaps, they may have also been misunderstood.

In 1989, Smith et al. reported 32 lesions with the histological features of Spitz nevi, 6 of which presented with lymph node metastases [1]. Smith et al. termed their cases as malignant Spitz nevi, because they found that such lesions displayed the histological characteristics of Spitz nevi and, although showing some atypical features, were not outside the range of Spitz nevi. Moreover, such tumors did not appear to display histological features sufficient to support a diagnosis of melanoma and did not seem to show “the potential of widespread metastasis” [1]. In 1995, Barnhill et al. reported 12 cases of melanocytic tumors with the histological characteristics of Spitz nevus and the atypical features previously described by Smith et al., classifying them on the basis of the clinical outcome. One case with a fatal course was labeled as Spitz-like melanoma, 2 cases with lymph node metastases as metastatizing Spitz tumors and 9 non-metastatizing cases as atypical Spitz tumors [2].

Piepkorn proposed that such tumors formed a wide spectrum, including benign lesions (Spitz nevi), which he considered uncommon, lesions with a uncertain malignant potential, globally estimated as low (atypical Spitz nevus), and malignant metastatizing lesions, which may have less competence for generalized metastasis than true melanomas (malignant Spitz nevi) [3]. To avoid an improper terminology, such an entire group of lesions has been termed as “spitzoid tumors” [4], but they can be better termed as Spitz tumors, because they do not resemble, but properly are the tumors originally described by Spitz in 1948. It is evident that, in this specific case, the word “tumor” is not used to evade a definite diagnosis [5], but because it is the best and simplest word to indicate a composite group of benign and malignant neoplastic lesions. It is also evident that, in this specific case, no one attributes mystical qualities to the word “tumor” [5], since it is used in conjunction with precise qualifying adjectives, such as “benign” or “malignant”, configuring a precise diagnosis (benign Spitz tumors or malignant Spitz tumors).

References

1. Smith KJ, Barrett TL, Skelton HG, et al. Spindle cell and epithelioid cell nevi with atypia and metastasis (malignant Spitz nevus). Am J Surg Pathol 1989; 13: 931-939.

2. Barnhill RL, Flotte TJ, Fleischli M, et al. Cutaneous melanoma and atypical Spitz tumors in children. Cancer 1995; 76: 1833-1845.

3. Piepkorn M. On the nature of histologic observations: The case of the Spitz nevus. J Am Acad Dermatol 1995; 32: 248-254.

4. Cerroni L. Spitzoid tumors. A matter of perspective? Am J Dermatopathol 2004; 26: 1-3.

5. Ackerman AB. Garble that derives from lack of definition. Am J Dermatopathol 2005; 27: 369-370.