MAMMARY CARCINOMA WITH NEUROENDOCRINE DIFFERENTATION

D. Rugnath, L.J. Dobbs, Jr., P. Strausbach, K. Hewan-Lowe
Brody School of Medicine at East Carolina University
Greenville, North Carolina

Introduction:
Electron microscopic examination of various breast lesions has demonstrated neuroendocrine granules in primary carcinoid tumor, metastatic carcinoid and a variety of in situ and infiltrative ductal carcinomas. Although the granules are argyrophilic, the nonspecific characteristic of this stain does not allow the distinction of neuroendocrine granules from lactalbumin and has confused the issue of
neuroendocrine mammary carcinoma. More specific immunohistochemical
stains have shown that the granules are polypeptide hormones. The following case illustrates that an integrated approach, consisting of clinical history, light microscopy, immunohistochemistry and electron microscopy are necessary for optimal classification of mammary neuroendocrine carcinoma.

Materials and Methods:
Paraffin embedded, four micron sections of a needle localization biopsy of a left breast mass from a 58 year old female were examined with hematoxylin and eosin stain. Immunohistochemical (IHC) stains for synaptophysin, chromogranin A, estrogen receptor, progesterone receptor and Her-2-neu were also studied. Electron microscopy was also performed on the paraffin embedded tissue.

Results:
Light microscopic examination revealed an infiltrating ductal carcinoma with some suggestion of neuroendocrine differentiation. Immunohistochemistry showed positive staining for estrogen receptor, progesterone receptor, synaptophysin and chromogranin. Ultrastructural demonstration of dense core, neurosecretory granules, verified the presence of neuroendocrine differentiation. The tumor did not show Her2/neu overexpression.

Discussion:
No history of prior carcinoma was found, which excluded a metastasis. Morphology typical of infiltrating ductal carcinoma was found, which excluded primary carcinoid tumor. Immunopositivity of the tumor for estrogen and progesterone receptors supported a breast primary. Dense core, secretory granules, seen ultrastructurally, were verified to be neuroendocrine in nature using IHC examination for synaptophysin and chromogranin. Evaluation of paraffin tissue was found to give adequate morphology for EM examination. Primary mammary carcinomas can express markers of neuroendocrine differentiation. Prognosis in these cases
remains uncertain. However, proper classification and case collection is needed to better assess the prognostic significance of neuroendocrine differentiation in mammary carcinomas.

ALVEOLAR SOFT PART SARCOMA: THEN AND NOW

Aruna Dash, Paul Strausbauch, Vinita Mathur, Karlene Hewan-Lowe
Brody School of Medicine at East Carolina University
Greenville, North Carolina.

Background:
Alveolar soft part sarcoma (ASPS) is a rare, sarcoma of unknown origin that involves the extremities and occurs in children and young adults. The organoid nests of eosinophilic cells, separated by sinusoidal vessels exhibit pseudoalveolar growth pattern. Over the past fifty years, there have been significant advancements in the characterization of this sarcoma. Morphology and intracytoplasmic
PAS-positive-diastase-resistant (PAS-D) crystals were once the key diagnostic elements. Later, ultrastructural examination demonstrated diagnostic intracytoplasmic rhomboid crystals. With the development of immunohistochemistry desmin positivity was noted in some ASPSs. A recent development is identification of monocarboxylate transporter 1 and CD147 in the cytoplasmic crystals. The distinctive, cytogenetic signature of ASPS is the unbalanced TFE-3 translocation, der(17)t(X;17)(p11.2;q25). We reviewed two cases of ASPS, which were diagnosed during a twelve year span and compared the diagnostic evaluation of these cases with the cumulative 50 year advances in diagnosis of alveolar soft part sarcoma.

Materials and Methods:
Case I: A forty-eight year old female presented with a tumor in the left lower leg. The tumor was examined with H and E, PAS-D. The immunohistochemical panel consisted of: cytokeratin, S-100-protein, chromogranin, smooth muscle actin (SMA), vimentin and neuron specific enolase (NSE).

Case II: A thirty-four year old female presented with a mass in the left infratemporal fossa. The tumor was examined with H and E, PAS-D. The immunohistochemical panel consisted of: pancytokeratin, low molecular weight cytokeratin, epithelial membrane antigen, SMA, S-100-protein, chromogranin, synaptophysin, desmin and TFE-3.

Samples from each tumor were fixed in 2.5 % glutaraldehyde and routinely processed for electron microscopy (EM).

Results:
Each tumor exhibited the characteristic morphology of ASPS with prominent vascular invasion. PAS-positive intracytoplasmic granular material was more prominent in the Case I sarcoma. Case I sarcoma cells were immunopositive for NSE. Case II sarcoma cells showed focal immunopositivity for desmin and TFE3. Epithelial markers, chromogranin, synaptophysin, SMA and S-100 protein were negative in each sarcoma. EM revealed diagnostic, intracytoplasmic, rhomboid, membrane bound paracrystalline structures with a periodicity of 6 nm.

Discussion:
The number of PAS-positive crystals in ASPS is variable and the low probability of finding these crystals makes this a poor diagnostic tool. EM increases the probability of finding the diagnostic crystals. The contribution of genogenic immunohistochemistry should not be underestimated since it may surpass the diagnostic utility of EM. The clinical application of knowledge of the chemical nature of the diagnostic crystal awaits further evaluation.

CYSTIC ATRIOVENTRICULAR NODE TUMOR: REAPPRAISAL OF THE CONTROVERSIAL ORIGIN OF THIS TUMOR
D. Rugnath, R. Mageau, J. Pestaner, J. Finley, P. Strausbauch, K. Hewan-Lowe
Brody School of Medicine at East Carolina University
Greenville, North Carolina

Introduction:
Cystic atrioventricular node tumor (CAVNT) is a rare tumor located in the region of the atrioventricular node (AV-node) . Although these benign tumors are often asymptomatic, they can cause lethal cardiac arrhythmias or heart block in young, apparently healthy individuals. In spite of detailed ultrastructural evaluation and selective use of specific immunohistochemical markers, there is persistent controversy as to the origin of this tumor. The proposed theory of mesothelial or
endothelial origin has been replaced by the concept of heterotopic proliferation of displaced, endothelial-cell clones of foregut origin. Heterotopia of the ultimobranchial body is also a possible origin. The finding of a CAVNT in a female, whose demise was precipitated by a lethal drug overdose, provided a unique opportunity for the reappraisal of the controversial origin of this tumor.

Materials and Methods:
A forty-five year old, apparently healthy female was found dead at her home. At autopsy a 1.5 x 0.5 x 0.5 cm, raised cystic tumor was found in the atrial septal region of the AV-node.

Paraffin embedded, four micron sections from the cystic tumor were examined with hematoxylin and eosin stain. The tumor was evaluated with the mucicarmine stain and immunohistochemical staining for pancytokeratin (AE1/3), B72.3, CD15, epithelial membrane antigen (EMA) and calretinin. A representative portion of the tumor was fixed in 2.5% glutaraldehyde and routinely processed for ultrastructural examination.

Results:
Light microscopic examination revealed cysts filled with amorphous material and lined by flat or cuboidal-type cells. The tumor cells were also present in nests and cords within a fibrous stroma. A few tumor-cell nests had glandular lumina. Immunohistochemical studies showed cytoplasmic staining for pancytokeratin, focal positivity for CD15 and luminal positivity for EMA. There was no staining for B72.3 and calretinin. Cytoplasmic staining for mucin was negative. Electron microscopy showed nuclei with deep clefts, central compact nucleoli and large irregular clumps of heterochromatin. Tonofilament bundles, scattered mitochondria and dilated profiles of rough endoplasmic reticulum were the dominant cytoplasmic organelles. Desmosome-like and primitive intercellular junctions were also noted. Although the cell membranes showed preservation artefact, no microvilli or residua of microvilli were identified.