Evaristo Sánchez Yus

Spitz nevus: a clinicopathological study of 349 cases.

Spitz nevus is an infrequent, usually acquired melanocytic nevus composed of epithelioid and/or spindle melanocytes that can occasionally be confused with melanoma. Currently, there are no immunohistochemical markers or molecular biology techniques that can be used to make an entirely safe diagnosis of Spitz nevus or melanoma in problematic cases. A retrospective study has been carried out that included all the cases diagnosed as Spitz nevus from our files. Follow-up information of the patients was unavailable. Three hundred forty-nine cases of unequivocal Spitz nevi were included, and their clinical and histopathological parameters were reviewed. One hundred and forty patients (40%) were 15 years old or younger, with a male to female ratio of 1:1. In patients older than 15 years, there was an evident predominance of women, with a male to female ratio of around 1:3. Spitz nevus was most commonly located on the lower extremities, followed by the trunk in both children and adults. Despite the fact that the head and neck were the third most common location in children, it was a much more frequent location in children than in adults. The constitution by epithelioid and/or spindled cells was the only histopathological finding present in 100% of cases. The other pathological findings studied were, from more to less frequent: maturation (72%), inflammatory infiltrate (70%), epidermal hyperplasia (66%), melanin (50%), telangiectasias (40%), Kamino bodies (34%), desmoplastic stroma (26%), mitosis (23%), pagetoid extension (13%), and hyalinization of the stroma (8%). Hyalinization was the only histopathological parameter that was statistically more frequent in adults than in children.

Intravascular and diffuse dermal reactive angioendotheliomatosis secondary to iatrogenic arteriovenous fistulas.

Reactive angioendotheliomatosis is a rare benign process that has been mainly described in patients with systemic infections, such as subacute bacterial endocarditis or tuberculosis, and in association with intravascular deposition of cryoproteins. Histopathologically, it is characterized by a proliferation of endothelial cells within vascular lumina resulting in the obliteration of the involved vessels. Another rare variant of reactive angioendotheliomatosis has been described in the lower extremities of patients with severe peripheral vascular atherosclerotic disease. It consists of violaceous and purpuric plaques histopathologically characterized by diffuse prolifrration of endothelial cells interstitially arranged between collagen bundles of the reticular dermis. This second variant has been named diffuse dermal reactive angioendotheliomatosis. We report two patients with reactive cutaneous angioendotheliomatosis appearing distally to arteriovenous fistulas used for hemodialysis because of chronic renal failure. The first patient showed intravascular reactive angioendotheliomatosis, while the second one had purpuric plaques that were characterized histopathologically by diffuse dermal angioendotheliomatosis. Both patients showed an arteriovenous “steal” syndrome with distal ischemia, and it is possible that a local increase of vascular endothelial growth factor, as is the case in hypoxia situations, induces the endothelial proliferation. To the best of our knowledge, cutaneous reactive angioendotheliomatosis has not been previously described in association with arteriovenous shunts.

Clear-cell atypical fibroxanthoma: an uncommon histopathologic variant of atypical fibroxanthoma

Atypical fibroxanthoma is a superficial variant of pleomorphic malignant fibrous histiocytoma. Histopathologically, it is characterized by a dermal nodule composed of bizarre cells arranged in a haphazard‐to‐fascicular pattern. These cells are spindle or rounded, pleomorphic and with numerous atypical mitotic figures. Some cells appear polygonal with ample and foamy cytoplasm. We recently encountered two elderly patients with atypical fibroxanthoma on their face. Histopathologically, one of the lesions was composed, almost entirely, of clear cells, whereas in the other one aggregations of clear cells constituted a half of the neoplasm. Atypical multinucleated cells with a Touton‐like appearance were present. In addition to clear cells, areas of more conventional atypical spindle cells arranged in fascicles were seen, supporting the diagnosis of atypical fibroxanthoma. PAS staining failed to demonstrate glycogen in neoplastic cells. Immunohistochemistry revealed that neoplastic cells expressed positivity for vimentin, muscle‐specific actin, and alpha smooth muscle actin, whereas cytokeratin, S‐100 protein, EMA, CEA, and clesmin were negative. Ultrastructural studies showed that neoplastic cells contained abundant rough endoplasmic reticulum, mitochondria, and numerous lipid vacuoles within the cytoplasm. Clear‐cell atypical fibroxanthoma is a rare variant of atypical fibroxanthoma that should be differentiated from other clear‐cell neoplasms of the skin.

Multiple sclerotic fibromas of the skin. A cutaneous marker of Cowden's disease.

Multiple hamartoma syndrome, or Cowdens disease, is a rare genodermatosis with multiple organ system involvement in which malignancy, particularly of breast and thyroid, may develop. Multiple trichilemmomas have been classically regarded as the cutaneous hallmark of this disease. We here emphasize multiple sclerotic fibromas of the skin as another specific cutaneous marker of this entity, which may also be helpful in an early diagnosis.

Epithelioid blue nevus: a rare variant of blue nevus not always associated with the Carney complex

Epithelioid blue nevus is a rare variant of blue nevus that has been recently described in patients with Carney complex. Some of the patients with Carney complex have multiple epithelioid blue nevi and a familial history of similar lesions is often recorded. Epithelioid blue nevus consists of an intradermal melanocytic nevus composed of polygonal epithelioid cells laden with melanin. Neoplastic cells show no maturation at the base of the lesion and, in contrast with the usual stromal changes in blue nevi, epithelioid blue nevus exhibits no fibrosis of the dermis. We have studied three cases of epithelioid blue nevus in three patients with no evidence of Carney complex. The lesions were solitary and there was no family history of similar lesions. Therefore, epithelioid blue nevus is a distinctive variant of blue nevus that may also appear as a sporadic lesion and is not always associated with Carney complex.

Lymphoepithelioma-like carcinoma of the skin: A light-microscopic and immunohistochemical study

Cutaneous carcinoma histopathologically resembling nasopharyngeal carcinoma has been termed lymphoepithelioma‐like carcinoma of the skin. We present an additional example of this rare cutaneous neoplasm that was located on the left temple of an 83‐year‐old woman. Serology for Epstein‐Barr virus was negative, and exploration of the nasopharyngeal region disclosed no abnormalities. Histopathologically, the neoplasm consisted of a relatively well‐circumscribed, dermal‐hypodermal nodule composed of irregular aggregates of epithelial cells with vesicular nuclei, some of them in mitosis, and scant cytoplasm. A dense lymphocytic infiltrate was present within the neoplastic aggregates, obscuring the epithelial component, and at scanning magnification, the lesion closely resembled cutaneous lymphoma or pseudolymphoma. There was local sebaceous differentiation. Immunohistochemistry showed positivity in the epithelial component for AE1/AE3 and AEB‐903 cytokeratins and negativity for 8–18 cylokeratins. The inflammatory infiltrate was positive for leukocyte common antigen, UCHL‐1, L‐26, Leu‐22, and OPD‐4 in variable proportions. Scattered cells within this inflammatory infiltrate were also positive for S‐100 protein, vimentin, HAM‐56, and MAC‐387. In situ hybridization investigations for the presence of Epstein‐Barr virus genomic DNA yielded negative results. Lymphoepithelioma‐like carcinoma of the skin is a distinct cutaneous neoplasm of unknown histogenesis, although some foci of adnexal differentiation have been found in some specimens. The possibility of cutaneous metastasis from occult nasopharyngeal carcinoma should be ruled out.

Epidermotropically metastatic breast carcinomas: Rare histopathologic variants mimicking melanoma and Paget's disease

Epidermotropic metastases from internal malignancies are exceedingly rare. We report two examples of epidermotropic metastatic breast carcinoma with striking intraepidermal involvement. The first case mimicked melanoma because the neoplastic cells contained melanin and were disposed both as single units and as nests at the dermoepidermal junction and throughout the epidermis. In the second case, the neoplastic cells were seen as isolated neoplastic cells with large, pale cytoplasm scattered throughout the epidermis, closely resembling extramammary Pagets disease. Immunohistochemical studies in both cases demonstrated the epithelial nature of intraepidermal neoplastic cells, which showed an immunophenotype identical to the neoplastic cells present in the dermis: positive staining with anti-cytokeratins, CEA, EMA, and GCDFP-15 and negative with anti-S-100 protein and HMB-45. These findings ruled out the possibility of a collision lesion, or simultaneous occurrence of melanoma and metastatic breast carcinoma. Pagetoid intraepidermal spread of metastatic breast carcinoma, as in our two cases, is exceptional. We also discuss the histogenetic similarities between our findings and those of mammary and extramammary Pagets disease, as well as the differential diagnosis of other cutaneous disorders characterized by pagetoid intraepidermal spread of neoplastic cells.

Giant dermatofibroma. A little-known clinical variant of dermatofibroma.

BACKGROUND Dermatofibroma is a common cutaneous lesion that usually appears as a slow-growing firm dermal nodule. OBJECTIVE Our purpose was to report the clinical and histopathologic characteristics of eight giant dermatofibromas and review the few cases of this variant of dermatofibroma reported in the literature. METHODS All clinical records of two Departments of Dermatology of University Hospitals from the past 5 years with a diagnosis of dermatofibroma were reviewed. Lesions that measured 5 cm or larger were considered for this study. Biopsy specimens were available from all lesions. RESULTS Giant dermatofibromas are most frequently on the legs, especially below the knee. Often they have a pedunculated appearance. Because of their large size, the correct diagnosis is not suspected clinically; a diagnosis of malignancy is often made. CONCLUSION Our findings indicate that giant dermatofibroma is a distinct but uncommon clinical variant of dermatofibroma that invariably exhibits a benign biologic behavior.

Miescher's radial granuloma. A characteristic marker of erythema nodosum.

We have studied 79 biopsy specimens of EN and 182 biopsy specimens of other types of panniculitis. Sixty (76%) of the 79 biopsy specimens of EN disclosed some MRG whereas none was found in the other types of panniculitis. MRG is a characteristic and easily recognizable structure, even at low magnification, and appears to be a useful marker of EN. A detailed study has also been made of the histologic features of EN. Its variations, as well as those of MRG, are related to the chronology of the nodule

Sebomatricoma: a unifying term that encompasses all benign neoplasms with sebaceous differentiation.

Literature regarding neoplasms with sebaceous differentiation is confusing, particularly concerning the concept of sebaceous epithelioma, accepted by some observers as a specific neoplasm but defined by others as basal cell carcinoma with sebaceous differentiation and still others as sebaceous adenoma in which undifferentiated basaloid cells predominate. From our study of 19 benign sebaceous neoplasms within this spectrum and a critical review of the literature, we conclude that (a) “sebaceous epithelioma” is a nonuseful term; (b) the term “basal cell carcinoma with sebaceous differentiation” should be used only for an otherwise conventional basal cell carcinoma with histological evidence of sebaceous differentiation; (c) “sebaceous adenoma,” as described by Rulon and Helwig, and “sebaceoma,” as described by Troy and Ackerman, represent polar ends of the spectrum of a benign neoplasm with varying degrees of sebaceous differentiation, for which we propose the term “sebomatricoma” and (d) sebomatricoma, so defined, embraces such diverse benign neoplasms with sebaceous differentiation as superficial epithelioma with sebaceous differentiation and previously “unclassifiable” sebaceous neoplasms, often found in patients with Muir–Torre syndrome or within nevus sebaceus of Jadassohn.