Quiz 21: What is your diagnosis?

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Diagnosis: Quiz 21

Quiz 21

Answer: Melanoma

Criteria for diagnosis clinically: An ill-defined plaque with a pink-orange-slightly brown cast covered in part by scale and on one side of it by scale-crust represents an unusual presentation of melanoma.

Differential diagnosis clinically: This could be misconstrued as Bowen's disease and biopsy is requisite to resolving the issue.

Criteria for diagnosis histopathologically: An asymmetrical neoplasm of strikingly abnormal melanocytes characterized (1) in the epidermis by nests that are not equidistant from one another, vary considerably in size and shape, have resumed peculiar outlines geometric, and have become confluent in loci, as well as by melanocytes disposed mostly as solitary units at all levels of it, including the cornified layer, and (2) in the dermis by confluence of aggregations of character similar to that in the epidermis, they, in loci, forming a sheet, is a melanoma.

Differential diagnosis histopathologically: There is none. 

Clinicopathologic correlation:  The plaque came into being mostly by virtue of the neoplastic melanocytes in a patchy front across the upper part of the dermis; the reddish hue is a consequence of venules dilated widely in the upper part of the dermis, they, in vivo, having been stuffed with erythrocytes; the paucity of brown derives from melanin being so scant; and the scale is a result of orthokeratosis.

Options for therapy predicated on knowledge of histopathologic findings: A melanoma must be excised in toto with just enough normal skin around it to ensure that that desideratum has been accomplished.

1) It is impossible, on grounds clinical alone, to make a diagnosis in this patient of melanoma. In fact, the lesion is much more consonant clinically with Bowen's disease than it is with melanoma, it being reddish and scaly and devoid largely of pigmentation. Biopsy, however, produced a specimen from which sections show melanoma indubitable.

2) The vaunted ABCDEs, much trumpeted as the surest route to clinical diagnosis of melanoma, fail miserably here-the C (Color variability) is missing.

3) As impossible as it is to make a diagnosis with specificity of melanoma clinically here, so easy it is to come to a diagnosis of melanoma histopathologically. The neoplasm shown in the photomicrographs fulfills all criteria for melanoma, both ones architectural and cytopathologic. The neoplasm is strikingly asymmetrical in all respects, including the surface and the base of it, as well as in terms of distribution of melanocytes and of lymphocytes. Moreover, nuclei of melanocytes are large, pleomorphic, and heterochromatic, and some are in mitosis.

4) The scale-crust so prominent clinically is not present in the 5-micron section of tissue pictured here.

5) The brown lesions on this patient's arm and forearm are seborrheic keratoses.

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