Clear-cell neoplasms

Wick MR, Ritter JH, Humphrey PA, et al. Clear cell neoplasms of the endocrine system and thymus. Semin Diagn Pathol. 1997 14 183-202. 

Clear Cell Neoplasm/Sugar Tumor/PEComa... 

Under the conditions of the study, there was clear evidence of carcinogenicity in rats as shown by squamous cell and basal cell neoplasms of the skin and in mice as shown by squamous cell carcinomas of the skin and ovarian neoplasms in females. No information has been reported on the carcinogenicity of VCD in humans. 

B cell neoplasms based on morphology, immunophenotype, and genotype often, but not always, correspond to stages of B cell development. However, some B cell lymphomas either do not clearly correspond to a specific developmental stage (i.e., appear to be of variable origin such as chronic lymphocytic leukemia/small lymphocytic lymphoma) or do not appear to be related to any known stage of normal development (i.e., hairy cell leukemia) (H10). 

The Ewing family of tumors comprises small round cell neoplasms of bone and soft tissue that are, in part, defined by a particular chromosomal aberration [t(ll 22)] and variants thereof. Over the past 15 years, it has become clear that ES and peripheral PNET are part of the same spectrum of neoplastic proliferations. Besides the karyotypic marker just mentioned, both of those tumor types also show neuroectodermal features in tissue culture and similarities in proto-oncogene expression. As classically defined, ES was distinguished from PNET by an absence of pseudorosettes and the lack of ultrastructurally or immunohistochemically detectable neuroectodermal features. However, this diagnostic separation is now considered to be antiquated and has been abandoned. 

Clear cell sarcoma (CCS) was formerly thought to represent a primary soft tissue counterpart of cutaneous malignant melanoma. Nonetheless, it is now known that CCS exhibits a consistent and characteristic t(12 22) chromosomal translocation that is not shared by mela-nocytic lesions of the skin. This neoplasm is typified by an epithelioid and/or spindle cell constituency, with a delicate fibrovascular stroma and clear or lightly eosinophilic cytoplasm. Melanin pigmentation may or may not be observed. 

The histologic appearance varies not only between tumors but also within the same neoplasm. Some areas of the tumor may be composed primarily of clear cells with only few widely scattered ducts, whereas other areas may be composed primarily of ducts. Sebaceous differentiation is also possible, as are other types of cellular differentiation such as oncocytic changes. 

Ellis GL. Glear cell neoplasms in salivary glands clearly a diagnostic challenge. Ann Diagn Pathol. 1998 2(l) 61-78. 

FIGURE 12.25 The neoplastic cells of this clear lung neoplasm contain melanosomes. X 16,000. 

Jewell LD, Barr JR, McCaughey WT, et al. Clear-cell epithelial neoplasms of the large intestine. Arch Pathol Lab Med. 1988 112 197-199. 

Clear cell variant of pancreatic endocrine neoplasm versus serous cystadenoma Diffuse immuno-reactivityforchromogranin and synaptophysin is highly in favor of an endocrine origin. 

Silva EG, Young RH. Endometrioid neoplasms with clear cells A report of 21 cases in which the alteration is not of typical secretory type. Am J Surg Pathol. 2007 31 1203-1208. 

Figure 20.1 shows a cerebral tumor from the lumbosacral region of a middle-aged woman. The H E-stained slide reveals a neoplasm with mainly epithelioid cells and a few clear cells, and abundant round to oval nuclei with fine chromatin (Table 20.6 see Fig. 20.lA). Its IHC is focally positive to epithelial membrane antigen (EMA) (see Fig. 20.IB). Boxes 20.1 and 20.2 show carcinoma, chordoma, craniopharyngioma, pituitary adenoma, and meningioma to be EMA positive. This tumor is negative for cytokeratin (CK) CAM5.2 (see Fig. 20.1C), so it does not fit the immunohistochemical...

BOX 20.1 Differential diagnoses of clear cell lesions. Unmarked boxes reflect neoplasms for which the feature or the... 

Bone metastases associated to renal neoplasm are suggestive of clear cell sarcoma. Rhabdoid tumor affects young children, and hypercalcemia and metastases at diagnosis are frequent in this highly aggressive tumor. Juvenile renal cell carcinoma occurs in the second decade and is frequently calcified and smaller than WT. Renal medullary carcinoma occurs in black adolescents with sickle cell trait involvement of the renal sinus results in caliectasis. Renal lymphoma is usually bilateral and associated with other sites of involvement. 

Among primary malignant soft-tissue neoplasm of the foot, synovial sarcoma and the clear cell sarcoma should be mentioned. Synovial sarcoma is... 

It has seemed pretty clear for several decades, from both studies in humans and in experimental settings, that carcinogenesis is a multistage process. At the broadest level, the process can be thought of as one in which a normal cell is first converted to a permanently deranged cell, which is called a neoplastic cell, and a second sequence in which the neoplastic cell develops into a tnmor, a neoplasm, that the pathologist can observe neoplastic conversion and neoplastic development. 

---