Sabato 27 ottobre 2012 - Pacini Editore

350
A combined lesion between melanoma
and squamous cell carcinoma
F.M. Bosisio1 , M.G. Valente2 , G. Cattoretti1 , M.S. Cuttin2 1 Università di Milano-Bicocca, Scuola di specialità aggregata Milano-
Milano Bicocca-Brescia, Monza; 2 AO San Gerardo, UO di Anatomia Patologica,
Monza
Introduction. In the field of the collision/combined tumors of the
skin, cases of epithelial-melanocytic lesions have been described,
though they remain quite rare entities. Among them, it is more
frequent to found basal cell carcinoma in association with melanoma.
Melanoma combined with a squamous cell carcinoma is a
more infrequent possibility. Here we report a case of combined
lesion of the skin composed by a V Clark level melanoma and a
minimally invasive squamocellular carcinoma.
Matherials and methods. The skin biopsy was sampled obtaining
a section along the minor axis, formalin-fixed and paraffinembedded.
Routine slides were obtained from the paraffin blocks
and stained with Hematoxilin-Eosin. Immunohistochemical analysis
was performed utilizing authomatic immunostaining system.
Results: case report. A 79-years-old woman presented a discromic
papular lesion on the right cheek, with a surface appearing
partly hyperkeratotic and partly ulcerated. The clinical diagnosis
was of basocellular carcinoma. At low magnification, it is recognizable
a dome-shaped figure, with an expanded epidermis
characterized by hyperkeratosis and by the presence of corneal
pearls. With the increase of the magnification, it becomes visible
more clearly a colonization of the expanded epidermis by atypical
spindle cells organized in nests that show wide confluence
and fusion among them. The nests show a destructive behavior
toward the epidermis leading to the ulceration of the epidermis
itself in the central part of the lesion. In the dermal portion,
the spindle cell population reached the ipodermal tissue, with
a depth of infiltration of 4,5 mm, and showed several mitoses
(> 6 / 10 HPF). No vascular nor perineural invasion were found.
Immunohistochemical stain for Melan-A antigen was perfomed,
which resulted positive in the spindle cells, identifying a population
of neoplastic melanocytes. HMB-45 resulted positive in the
deep dermal part of the lesion (Fig. 1). No superficial spread
was present at the shoulder of the lesion. A diagnosis of nodular
melanoma at V Clark level, pT4b, was made. Nevertheless, the
epidermis surrounding the melanoma presented severe keratinocyte
atypia, and undefined borders with single keratinocytes
infiltrating the papillary dermis (Fig 2). Immunostain with CK
AEI-AE3 resulted perfectly complementary to the melanocytic
stain, highlighting the invasive single cell component of the
neoplasia. Therefore, a diagnosis of invasive squamous cell carcinoma
in association with the previously described melanoma
was made.
Discussion and conclusion. When two neoplasm are found
together, they must be categorized according to Satter et al. 1 as
collisions tumors if are adjacent but separated; combined tumors
if there are 2 or more cell population admixed in the same lesion;
colonized tumors if one population permeates an underlyng
second tumor, with the condition that the colonizing tumour must
remain localized within the limits of the second tumoral population;
and biphenotipic tumors when the two different population
exhibit coexpression of phenotypically different immunohistochemical
markers. In our case, the two tumoral population were
admixed, so this must be considered a combined tumor. Combined
melanocytic-epithelial lesions are rare. A benign example
of such entity is the melanoacanthoma, where in-between the
limits of a keratinocytic acanthoma is homed a proliferation of
benign melanocytes throughout the thickness of the acathoma 2 .
Malignant lesions are similarly rare. The most frequent association
is between melanoma and basal cell carcinoma. The association
between melanoma and squamous cell carcinoma is far more
infrequent 3 . The association melanocytic-epithelial lesion has
CONGRESSO aNNualE di aNatOmia patOlOGiCa SiapEC – iap • fiRENzE, 25-27 OttOBRE 2012
Fig. 1. the melanoma is entirely homed into the squamous cell carcinoma
(a). HmB45 stains a deep clonal nodule of the vertical growth
phase of the melanoma (B). Cytokeratines aE1-aE3 stain (C) is perfectly
complementary with maRt-1 stain (d).
been found also in other organs. A case of atypical melanocytic
hyperplasia resembling melanoma in situ was described also in
association with multiple foci of squamous cell carcinoma in
situ in the esophagus. The peculiarity of this case was that at
the follow up the lesion regressed, so that the authors concluded
the paper establishing the reactive nature of the lesion, the same
as the typical melanocytosis of the esophagus that can be found
associated with invasive squamocellular carcinoma 4 . Non neoplastic
melanocytes can be trapped and proliferate in an epithelial
neoplastic lesion also in the skin 3 . In our case, the more malignant
lesion is the melanoma, which is a > 4 mm thick and at the
V Clark level, compared with the squamous cell carcinoma, that
presents only some invasive foci. It is difficult to assess the prognosis
of these tumors due to the rarity, but in our case the more
advanced stage of the melanoma component easily will determine
the prognosis of the patient.
Fig. 2. on the shoulder of the lesion atypical keratinocytes are visible
infiltrating the papillary derma (a); this is easier to see with the
cytokeratines staining (B). Nests of atypical melanocytes permeates
all the squamous cell carcinoma (C).