Metastatic carcinoma from the bladder
Criteria for diagnosis clinically: Violaceous papules, but mostly plaques of shapes bizarre, they being geometric and largely polycyclic, are changes that in this instance are those of metastases from carcinoma of the bladder.
Differential diagnosis clinically: The attributes clinical are so unusual that no differential diagnosis meaningful can be generated.
Criteria for diagnosis histopathologically: Neoplastic cells with large, pleomorphic, hyperchromatic nuclei and discernible pink cytoplasm are present within widely dilated lymphatics and in the interstitium in the upper part of the dermis, those being changes of metastatic carcinoma that in this patient came from a primary in the bladder.
Differential diagnosis histopathologically: That this is a metastasis cannot be challenged, but the precise nature of the primary carcinoma cannot be inferred from the findings alone in this section of skin.
Clinicopathologic correlation: The lesions are elevated because of the infiltrates of neoplastic cells; they are purplish because, in vivo, venules in the upper half of the dermis are dilated markedly and their lumen is replete with erythrocytes, which also are extravasated in the reticular dermis; and the surface of the lesion is smooth because the cornified layer is normal.
Options for therapy predicated on knowledge of histopathologic findings: Sad to say, a patient with metastatic disease such as this has a poor prognosis, irrespective of what therapy is attempted.
(1) The features clinical in this patient are so extraordinary that considerations diagnostic cannot be conventional. Unless one has had experience with another patient whose lesions were very similar to these and that proved to contain metastases, it would be impossible to come to a diagnosis clinical with certainty here.
(2) It is easy in this section of tissue to make a diagnosis of carcinoma metastatic to skin because lymphatics are stuffed with cells of the carcinoma, that being proof positive of metastasis.
(3) Although in this particular instance it is impossible to determine the site of the primary carcinoma, that is not the case always in regard to metastases to skin. For example, it is possible, with confidence, to diagnose many an example of metastatic thyroid carcinoma, metastatic breast carcinoma, metastatic stomach carcinoma, metastatic renal-cell carcinoma, and metastatic melanoma to skin. The attributes cytopathologic of the metastasis are just like those of the primary.
(4) The presentations clinical of metastases to skin are as protean as are the appearances histopathologic, ranging from a solitary papule to countless nodules. In this patient, all of the lesions are purplish plaques. The variations are numerous.
(5) Although any site anatomic of skin can be visited by malignant neoplastic cells of a metastasis, the scalp is a favorite for many a type of carcinoma. Not uncommonly, melanoma metastasizes to skin. Sadly, it often has predilection for the brain.