Oncocytic Melanoma: A Study of a Rare Entity.

The authors report the second case of oncocytic melanoma, one of the rarest known melanoma variants. The diagnosis was established by Fontana stain positivity, expression of S100 protein as well as gp100/HMB45, and demonstration of numerous mitochondria by ultrastructure. Because it is known that some oncocytic tumors of the thyroid gland and kidney contain point mutations and common deletions of mitochondrial DNA, the complete mitochondrial DNA of the reported oncocytic melanoma was also studied. It was normal except for 2 private separate point mutations, predicted to be not pathogenic, which do not seem to play any role in the tumor phenotype.

A Focus of Differentiated Myeloid Sarcoma in a Ligation Specimen of the Fallopian Tube: No Evidence of Hematologic Abnormality in 18 Years of Follow-up Despite Absence of Treatment.

A 0.2-cm intramural focus composed predominantly of myelocytes and metamyelocytes, many CD3+, CD43+ T-lymphocytes, scanty CD20+ B-lymphocytes, rare mast cells, but no eosinophils or myeloblasts was incidentally found in a ligation specimen of the left fallopian tube. The myeloid cells were positive for chloroacetate esterase, myeloperoxidase, myeloid marker BM2, and CD43, and they were negative for CD30, CD34, CD117, ERG, and TDT. The findings in the left fallopian tube were consistent with the diagnosis of differentiated myeloid sarcoma. The right fallopian tube was normal. No hematologic abnormalities were found elsewhere in the body. Curiously, the patient remains free of any hematologic abnormality for 18 years despite absence of treatment.

Perineurioma of the adrenal gland.

The authors report the first case of perineurioma of the adrenal gland. The tumor was composed of elongated wavy spindle cells focally arranged in a fascicular pattern. It was positive for epithelial membrane antigen (EMA) and claudin-1, and was negative for S-100 protein and glial fibrillary acidic protein (GFAP). Electron microscopy showed long, slender cytoplasmic processes coated by discontinuos basal lamina and presence of many pinocytotic vesicles.

Mutation of the INI1 gene in composite rhabdoid tumor of the endometrium.

Composite rhabdoid tumors are typically adult tumors that contain a component of rhabdoid cells, which are characteristic of the aggressive childhood malignant rhabdoid tumor. Pediatric rhabdoid tumors are characterized by the inactivation of the hSNF5/INI1/SMARCB1 gene, with subsequent loss of expression of the protein. In contrast, only a single composite rhabdoid tumor has demonstrated involvement of the INI1 gene. In our study, INI1 protein expression was studied in 2 uterine carcinosarcomas with rhabdoid components (composite rhabdoid tumors). The rhabdoid component of 1 tumor showed lack of immunoreactivity for the INI1 protein and strong positivity for cyclin D1, whereas the adenocarcinomatous component of the tumor and both components of the second tumor were immunoreactive for the INI1 protein and negative for cyclin D1. Loss of one INI1 allele and a mutation in exon 7 of the remaining allele were detected in the first tumor, consistent with the immunohistochemistry results. Our results demonstrate that deletions and mutations of the INI1 gene can occur also in rare composite rhabdoid tumors of adulthood. Further studies are necessary, however, to determine the prognostic significance of this finding.

A clonal t(8;12)(p11.2;q24.3) as the sole abnormality in a solitary fibrous tumor of the pleura.

A case of solitary fibrous tumor of the pleura with the karyotype 46,XY,t(8;12)(p11.2;q24.3) is reported. Although rearrangement of 12q15 approximately 24 is a recurring abnormality in solitary fibrous tumors, rearrangement of chromosome 8 was previously unreported in these tumors.

Leiomyoma of the urinary bladder: a cytogenetic study of a case.

We report the first case of a leiomyoma of the urinary bladder studied by cytogenetics. In comparison with cytogenetic changes of leiomyomas of other sites, the karyotype of the tumor was unusual: 47,XX,+7/89 approximately 93,XXXX,-1,+7,+7,add(12)(q23.4),+add(12)(q23.4),-18,-21,+idic(21)(p11.2),-22.

Deletion (21)(q21.2q22.12) as a sole clonal cytogenetic abnormality in a lobular capillary hemangioma of the nasal cavity.

A clonal deletion (21)(q21.2q22.12) was detected as a sole cytogenetic abnormality in a lobular capillary hemangioma (pyogenic granuloma) of the nasal cavity. This finding supports a neoplastic, rather than reactive, nature for this lesion. To our knowledge, these rare lesions have not previously been studied by cytogenetics.

A clonal translocation (7;8)(p13;q11.2) in a leiomyoma of the vulva.

We present the first case of a vulvar leiomyoma studied by cytogenetics. The tumor formed a 3.0-cm periurethral nodule in a middle-aged woman and was positive for the muscle markers desmin and caldesmon, and for estrogen and progesterone receptors. Its karyotype was 46,XX,t(7;8)(p13;q11.2). This translocation has not been described in previously reported leiomyomas, regardless of their site of origin. The transcription factor PLAG1 gene at 8q12 was not altered by the translocation.

Malignant nonteratoid ocular medulloepithelioma in a llama (Llama glama).

A 6-year-old female llama presented with buphthalmos of its right eye owing to the presence of an intraocular mass. The affected globe was enucleated and submitted for microscopic examination. The intraocular mass was diagnosed as malignant medulloepithelioma. Within the following months, the llama developed soft tissue masses, which completely filled the right orbital cavity and expanded the cranial portion of the right mandibular bone, and enlarged mandibular lymph nodes. Euthanasia was elected 30 months after the initial diagnosis. The carcass was submitted for postmortem examination, which revealed the presence of medulloepithelioma metastases within the right orbit, mandible, mandibular lymph nodes, lungs, liver, and mesenteric and sublumbar lymph nodes. The primary intraocular tumor and its metastases were composed of neoplastic undifferentiated neuroepithelial cells, which formed tubules, Flexner-Wintersteiner and Homer Wright rosettes, and rare solid sheets. Electron microscopy showed that tumor cells were connected by desmosome-like junctions and contained rare intracytoplasmic basal bodies. Neoplastic cells were positive for vimentin, nestin, microtubule-associated protein 1B, S-100 protein, and glial fibrillary acidic protein (GFAP). To the best of the authors' knowledge, this is the first report of a malignant nonteratoid ocular medulloepithelioma with distant metastases in a llama and of the ultrastructural and extended immunohistochemical characterization of a nonteratoid medulloepithelioma in this species.

Rhabdoid Myomelanocytic Tumor (PEComa) of the Ovary: A Clinically Benign Case Followed for 7 Years.

A 3.0 × 2.5 cm rhabdoid myomelanocytic tumor was incidentally found in the left ovary of a 43-year-old black woman. The tumor cells were cytologically bland with minimal proliferation rate, multifocally weakly or moderately expressed TFE3, strongly expressed smooth muscle markers and SMARCB1/INI1, and focally expressed HMB45. They contained numerous paranuclear whorls of intermediate filaments that were verified by ultrastructure. No other lines of differentiation were detected within the tumor. Neither translocation nor increased number of copies of the TFE3 gene at Xp11.22 was detected by fluorescence in situ hybridization. The patient remains well, free of tumor, 7 years after surgery. A rhabdoid variant of myomelanocytic tumor is a rarity, with only a single case described previously.

A clonal dic(16;21)(p13.1;p11.2)del(16)(q11.1), with gains of several chromosomes and monosomy 21, in a case of splenic hamartoma: evidence for its neoplastic, not hamartomatous, origin.

Cytogenetic examination of a case of splenic hamartoma led to the discovery of a clonal population with the karyotype 47 approximately 58,XX,+X,+4,+5,+5,+6,+10,+12,+14,der(16)dic(16;21)(p13.3;p11.2), dic(16;21)del(16)(q11.1),+17,+19,+20,-21. This finding is indicative of a neoplastic, not hamartomatous, origin for this lesion.

Primary myeloid sarcoma of the testicle with t(15;17).

The first case of acute promyelocytic leukemia presenting as a solitary testicular mass (myeloid sarcoma) that relapsed in the contralateral testicle is described. The neoplastic cells strongly expressed chloroacetate esterase, myeloperoxidase, CD33, CD43, and weakly, CD117. The presence of many azurophil granules and Auer rods was detected by electron microscopy. Translocation (15;17)(q22;q21.1) was revealed by cytogenetics and was verified by fluorescence in situ hybridization. Contralateral testicle is a favorite site for recurrence in a subset of testicular myeloid sarcomas. Subclassification of all cases of myeloid sarcoma ought to be attempted.

Thymic Tumor With Adenoid Cystic Carcinoma-Like Features: A Study of a Clinically Favorable Case Followed for 9 Years.

Thymic tumors with adenoid cystic carcinoma-like features are true rarities, with only 6 cases reported. Our knowledge of their clinical behavior is insufficient. We present a case of a noninvasive cribriform tumor that was followed, including a 4-year period after tumor resection and radiation therapy, for a total of 9 years. The tumor was purely epithelial. It was positive for keratins (AE-1/AE-3, CK19, 34ßE12,CK5/6), MOC-31, P63, P40, CD10, and MYB, and was negative for myoepithelial or neuroendocrine markers. Presence of cell processes, desmosome-like junctions with tonofilaments and multifocally reduplicated basal lamina was noted on ultrastructural examination. Two signals of the MYB gene per cell were detected by fluorescence in situ hybridization. No monosomy or translocations of the gene were found. Although additional clinical studies are necessary, it seems that indolent behavior of cribriform noninvasive subset of these tumors may be anticipated.

Peripheral medulloepithelioma: an immunohistochemical, ultrastructural, and cytogenetic study of a rare, chemotherapy-sensitive, pediatric tumor.

A case of peripheral medulloepithelioma, a rapidly growing tumor involving the pelvic cavity of a 12-year-old girl, is presented. The diagnosis was supported by expression of vimentin, nestin, alpha-internexin, neurofilaments, and microtubule-associated protein 5 and by characteristic ultrastructure that included absence of cilia or microvilli. Trisomy of chromosomes 2 and 8 was the only detectable chromosomal abnormality. Combination chemotherapy resulted in complete remission. Because some of these rare tumors are sensitive to chemotherapy, their recognition and separation from other neuroectodermal tumors are advisable for better understanding of their biology and determination of optimal treatment.

Fusion of the FUS and ATF1 genes in a large, deep-seated angiomatoid fibrous histiocytoma.

We report a case of a large, deep-seated, diagnostically difficult angiomatoid fibrous histiocytoma. The neoplastic cells were positive for vimentin, calponin, CD99, and, focally, for desmin and contained intertwining cytoplasmic processes joined by desmosomelike junctions. Fusion of codon 175 of the gene to codon 110 of the gene was detected by reverse transcription-polymerase chain reaction. Because identical fusion of the and genes has been recently reported in another case of angiomatoid fibrous histiocytoma, fusion of these genes may be characteristic for at least a subset of these tumors.

Overexpression of the BCL2 gene in a Sertoli-Leydig cell tumor of the ovary: a pathologic and cytogenetic study.

A case of virilizing ovarian Sertoli-Leydig cell tumor overexpressing the BCL2 gene and including a novel clonal chromosomal rearrangement of chromosome 18, der(5)t(5;18)(p13;q12),+6,+12, der(18)r(5;18)(p15.3p13;p11.3q12) is described. Further studies of these rare tumors are necessary to ascertain the significance of the findings.

Cardiac myxoma: a cytogenetic study of two cases.

Two cases of cardiac myxoma, each arising in the left atrium, are presented. One tumor contained the clonal abnormality i(17)(q10),der(20)t(1;20)(q21;q11.2) and the second tumor contained add (9)(p22),+12. Such rearrangements have not been previously reported in these tumors.

Detection of ganglion cells in the colonic plexuses by immunostaining for neuron-specific marker NeuN: an aid for the diagnosis of Hirschsprung disease.

The majority of ganglion cells in the colonic plexuses can be easily and specifically identified by immunostaining for neuronal marker NeuN. The distance between the neighboring solitary ganglion cells or groups of ganglion cells varied from 0.18 to 4.0 mm, average 1.0 mm, in ganglionic segments of colons of patients with Hirschsprung disease, and from 0.3 to 6.3 mm, average 1.43 mm, in colons of pediatric patients with chronic constipation of various etiologies. No ganglion cells were detected in aganglionic colonic segments of patients with Hirschsprung disease by this method.