[Unusual non-neoplastic lesions in the "surgical pathology" of the thyroid]

This review aims to describe and assist in the categorization of most of the unusual non-neoplastic conditions, encountered in the surgical pathology of the thyroid. The conditions included are: normal intrathyroidal vestigial tissues/structures (i.e. rests of the ultimobranchial body and thyroglossal duct) and their relevant pathological derivatives (ultimobranchial body cyst, intrathyroidal lymphoepithelial cyst, thyroglossal duct cyst); mature intrathyroidal heterologous tissues/organs of either metaplastic or heterotopic origin (adipose tissue, striated skeletal muscle, cartilage, parathyroid glands, thymus, salivary gland tissue) and their relevant pseudotumoural lesions; varieties of metaplastic and non-metaplastic morphologic changes of the thyroid follicular epithelium (oncocytic, clear cell/signet ring cell, darkly pigmented cell, mucinous (myxoid), squamous, spindle cell); amyloid goiter; some reactive and/or degenerative cytologic and nuclear atypicalities (nuclear pseudoclearing and cell pleomorphism) as well as some hyperplastic or peculiar growth patterns (capsular pseudoinvasion; vascular invasion; papillary carcinoma-like and paraganglioma-like patterns) of benign conditions mimicking neoplasia; and finally. some pseudotumoural lesions of the stroma (pseudoangiosarcomatous vascular proliferation, and post-fine-needle aspiration spindle cell nodule). The pathogenetic mechanism, the morphologic interpretation, and the differential diagnosis of each of the above-listed conditions are discussed and pertinent illustrations for many of them are also provided. Lesions of thyroid tissue situated outside of the gland itself are not discussed.

Clinical case seminar: in vivo and in vitro characterization of a novel germline RET mutation associated with low-penetrant nonaggressive familial medullary thyroid carcinoma

CONTEXT

RET mutation analysis provides useful information on the clinical outcome of medullary thyroid carcinomas (MTCs) and the risk of disease in the family members.

OBJECTIVE

The objective of this study was to document genotype-phenotype relationships in an Italian family with a novel RET mutation.

DESIGN/SETTING

RET gene alterations were investigated in a patient with unifocal MTC and her relatives. The identified mutation was subjected to in vitro functional testing.

PATIENTS

Patients included a female proband who developed MTC at age 60, her five children, and three grandchildren.

MAIN OUTCOME MEASURES

DNA extracted from the blood and the proband's tumor were analyzed for RET alterations. The transforming potential and mitogenic properties of the identified mutation were investigated.

RESULTS

A novel heterozygous germline RET mutation at codon 777 (AAC-->AGC, N-->S) (RET/N777S) was identified in the proband and three of her relatives. Two of the latter presented thyroid nodules, but none had MTC or C cell hyperplasia. The proband's MTC was characterized by late onset and limited aggressiveness, with no evidence of regional lymph node or distant metastases 10 yr after total thyroidectomy. This phenotype is consistent with the RET/N777S mutant's low-grade transforming potential and limited activation of RET tyrosine kinase.

CONCLUSION

Our findings indicate that the newly identified RET/N777S mutation is a low-penetrant cause of MTC disease. This phenotype might be less aggressive than that associated with MEN2A of familial MTC, although close clinical follow-up of carriers is essential.

Renal cystic diseases: a review

This review aims to assist in the categorization of inherited, developmental, and acquired cystic disease of the kidney as well as to provide a pertinent, up-to-date bibliography. The conditions included are autosomal-dominant polycystic kidney disease, autosomal-recessive polycystic kidney disease, unilateral renal cystic disease (localized cystic disease), renal simple cysts, multicystic dysplastic kidney, pluricystic kidney of the multiple malformation syndromes, juvenile nephronophthisis and medullary cystic disease, medullary sponge kidney, primary glomerulocystic kidney disease, and glomerulocystic kidney associated with several systemic disorders mainly of genetic or chromosomal etiology, cystic kidney in tuberous sclerosis, and in von Hippel-Lindau syndrome, cystic nephroma, cystic variant of congenital mesoblastic nephroma, mixed epithelial stromal tumor of the kidney, renal lymphangioma, pyelocalyceal cyst, peripylic cyst and perinephric pseudocyst, acquired renal cystic disease of long-term dialysis, and cystic renal cell carcinoma and sarcoma. Whereas the gross and histologic appearance of some of these conditions may be diagnostic, clinical and sometimes molecular studies may be necessary to define other types.

Adenosis tumor of anogenital mammary-like glands: a case report and demonstration of clonality by HUMARA assay

In mammary pathology, adenosis tumor is defined as a clinically recognizable lesion that histologically primarily consists of adenosis, but also exhibits various combinations of diverse epithelial changes seen in other benign breast diseases. A lesion that occurred in the anogenital area of a 46-year-old woman and apparently arose in anogenital mammary-like glands is described and which, in our opinion, is best classified as adenosis tumor. A biopsy revealed a well-demarcated, unencapsulated lesion surrounded by compressed fibrous tissue forming a pseudocapsule. Several histological patterns within the same tumor mass were recognizable: sclerosing adenosis-like changes, variably sized microcysts and cysts, some with rare short papillary projections having hyalinized cores, rare tubular structures exhibiting epithelial features reminiscent of simple ductal hyperplasia, areas with oxyphilic (apocrine) metaplasia, and clear cell epithelial changes resembling mucinous metaplasia. Decapitation secretion was notable in many lumens. Rare lumens were filled with foamy macrophages. There were also focal clear cell changes of myoepithelial cells. The stroma was paucicellular and sclerotic in some foci and composed of myofibroblasts and myxoid in others. Calponin, actins, and p63 stained myoepithelial cells. The cells in the oxyphilic (apocrine) metaplasia areas stained for mitochondrial antigen and Bcl-2. Antibodies to progesterone and estrogen receptor stained approximately 50 and 20% of the epithelial cell population, respectively. Human androgen receptor gene analysis yielded a monoclonal pattern. As our case exhibited a number of patterns identical to those seen in diverse benign breast diseases, its classification as adenosis tumor seems justifiable. This cutaneous perianal lesion is indistinguishable microscopically from its mammary analogue and was clinically detectable.

Mt 21-42: development and validation of an automatic device proposed for the endoscopic diagnosis of Helicobacter pylori infection and atrophic gastritis

BACKGROUND

Gastric juice may give important clinico-pathological information, but measurements in this medium are difficult. In this study we present and validate an innovative device (Mt 21-42) performing gastric juice analyses during endoscopy and proposed for the endoscopic diagnosis of Helicobacter pylori infection and hypo/achlorhydria.

METHODS

Analyses on both aqueous solutions (80 pH buffer + 120 ammonium chloride samples) and human gastric juice were carried out to assess the measuring performance of Mt 21-42 on the ideal and real matrix, respectively. Matrix spike and manipulation tests were also performed to investigate the matrix effect of gastric juice and to evaluate the consequences of its manipulation on the measurements. Furthermore, preliminary clinical tests were performed to evaluate the clinical potentiality of the device.

RESULTS

Mt 21-42 showed a good measuring performance on ideal matrix (coefficient variation: pH = 1.3%, ammonium = 2.1%) and real matrix (coefficient variation: pH = 1.2%, ammonium = 1.9%). Analyses on gastric juice excluded a substantial matrix effect (percent recovery =96.5-98.7%) but demonstrated a significant influence of manipulation procedures (p < 0.05).

CONCLUSIONS

Human gastric juice does not have a substantial matrix effect for pH and ammonium determination, but its manipulation may affect the measurement of these components. Mt 21-42 represents a precise instrument for the measurement of gastric juice and a potential precious tool for the endoscopic detection of H. pylori infection and hypo/achlorhydric conditions.

Real-time detection of Helicobacter Pylori infection and atrophic gastritis: comparison between conventional methods and a novel device for gastric juice analysis during endoscopy

BACKGROUND AND STUDY AIMS

Gastric juice may represent a valuable source of clinicopathological information if properly analyzed. We evaluated the reliability and clinical validity of data obtained using an innovative device (the "Mt 21-42") that analyzes gastric juice, thus allowing the identification of Helicobacter pylori infection and atrophic gastritis of the oxyntic mucosa during endoscopy.

METHODS

Validation studies were carried out to evaluate the measuring performance of the device. In addition, the H. pylori status and the presence of atrophic gastritis were assessed in 150 patients undergoing upper gastrointestinal endoscopy. In all these patients the Mt 21-42 device was used to assist endoscopy. Conventional tests (involving histology, urease testing, urea breath testing, anti- H. pylori IgG, serum gastrin, pepsinogen, intrinsic factor and parietal cells autoantibodies, vitamin B12, and folate) were also performed for comparison with the Mt 21-42 results.

RESULTS

The measuring performance of the Mt 21-42 was good; for pH, the relative percent error and the coefficient of variation were 1.9 % +/- 4.2 and 1.3 %, respectively, and for ammonium they were 0.1 % +/- 0.2 % and 2.1 %. For the detection of H. pylori infection, the sensitivity and specificity of the device (96.7 % and 94.3 %) were similar to those of the urea breath test (90.5 % and 93.3 %) and serology (87.1 % and 88.8 %), and higher than those of the urease test (78.6 % and 98.7 %; P < 0.01) and routine histology (94.3 % and 76.3 %; P < 0.05). When compared with the currently available standard methods, use of the Mt 21-42 was found to be the most sensitive technique for the detection of atrophy (94.7 % vs. 5.3 % - 47.4 %; P < 0.001); the device failed to detect the disease in only one case (5 %), whereas failure rates of 53 % - 95 % were reported with the conventional methods.

CONCLUSION

Atrophic gastritis of the oxyntic mucosa is a risky condition that often goes undetected in current clinical practice. The Mt 21-42 is an effective, useful, and desirable tool that may help to overcome this diagnostic limitation; it produces time and cost savings and also allows the detection of H. pylori infection.

Pseudoangiomatous Stromal Hyperplasia in Lesions Involving Anogenital Mammary-Like Glands

Pseudoangiomatous stromal hyperplasia (PASH), first reported in 1986, is nowadays a well-recognized change in the breast. We present three cases of lesions involving anogenital mammary-like glands demonstrating this feature. All patients were females (ages, 42, 43, and 53 years). Each presented with a solitary, 1.5- to 2-cm asymptomatic nodule. Locations included the perianal area, perineum, and labium majus. Histopathologically, one lesion was classified as low-grade phyllodes tumor, another as fibroadenoma, and in the remaining case PASH was found in the background of mild hyperplasia of anogenital mammary-like glands and substantial lipomatous metaplasia. In all lesions, PASH had an identical appearance to that in the breast, that is open, slit-like, often anastomosing channels devoid of erythrocytes and lined by discontinuous, often attenuated, inconspicuous cells without atypia or mitotic activity set in a hyalinized collagenous stroma. Quantitatively, PASH ranged in the above cases, forming a relatively small focus in the fibroadenoma and being quite extensive in the remaining two cases. In the phyllodes tumor, PASH areas exhibited focal hypercellularity and presence of myoid cells. In none of the cases were there cells with intranuclear inclusions or multinucleated cells. The lesions were surgically excised. Two patients with follow-up were disease-free at one and three years after the operation. As to our knowledge, PASH has not been previously described in the anogenital area, this feature seems to have been either overlooked or is genuinely rare in this location. It may occur in a preexisting lesion of anogenital mammary-like glands or may apparently by itself produce a clinically detectable lesion. The clinicopathologic features of PASH in the anogenital area seem to be identical to those in the breast.

Cervical cyst of the ligamentum flavum and C7-T1 subluxation: case report

A patient with progressive gait disturbance resulting from a cyst of the cervical ligamentum flavum associated with C7-T1 listhesis is reported. Surgical removal of the cyst improved the patient's myelopathy. Intraspinal degenerative cysts are preferentially located in the lumbar region:unusual is the cervical localization. Differential diagnosis includes ligamentum flavum cyst, synovial and ganglion cysts. Association between degenerative intraspinal cysts and listhesis is discussed. To our knowledge, this is the first case of cyst of the ligamentum flavum associated with cervical subluxation.

Mucinous Carcinoma of the Skin, Primary, and Secondary

We present the largest series of mucinous carcinoma involving the skin, describing the histopathologic, immunohistochemical, electron microscopic, and cytogenetic findings. Our aim was fully to characterize the clinicopathologic spectrum and compare it with that seen in the breast. In addition, we wished to reevaluate the differential diagnostic criteria for distinguishing primary mucinous carcinomas from histologically similar neoplasms involving the skin secondarily, and study some aspects of their pathogenesis. We demonstrate that primary cutaneous mucinous carcinomas span a morphologic spectrum compatible to their mammary counterparts. Both pure and mixed types can be delineated morphologically, and some lesions have mucocele-like configurations. Most lesions seem to originate from in situ lesions that may represent, using mammary pathology terminology, ductal hyperplasia, atypical ductal hyperplasia, or ductal carcinoma in situ or a combination of the three. Inverse cell polarity appears to facilitate the progression of the changes similar to lesions in the breast. The presence of an in situ component defines the neoplasm as primary cutaneous, but its absence does not exclude the diagnosis; although for such neoplasms, full clinical assessment is essential. Mammary mucinous carcinoma involving the skin: all patients presented with lesions on chest wall, breast, axilla, and these locations can serve as clue to the breast origin. Microscopically, cutaneous lesions were of both pure and mixed type, and this correlated with the primary in the breast. Dirty necrosis was a constant histologic finding in intestine mucinous carcinomas involving the skin, and this feature may serve as a clue to an intestinal origin.

Adrenocortical oncocytic tumors: report of 10 cases and review of the literature

Ten additional adrenocortical oncocytic tumors are presented: 2 benign oncocytomas, 4 borderline oncocytomas of uncertain malignant potential, and 4 oncocytic carcinomas. Histologically all tumors were entirely or predominantly composed of oncocytes. Immunohistochemically all tumors were immunoreactive for mitochondrial antigen mES-13. Electron microscopy was performed in 8 cases and was confirmatory of the oncocytic cell change. The morphologic parameters of the Weiss system, considered to be predictive of the biologic behavior of conventional (nononcocytic) adrenocortical tumors, are reviewed in the context of their possible application to the oncocytic tumor variant. Proposed major criteria (high mitotic rate, atypical mitoses, venous invasion) and minor criteria (large size and huge weight, necrosis, capsular invasion, sinusoidal invasion) in distinguishing malignant tumors are discussed, and definitional criteria (predominantly cells with eosinophilic and granular cytoplasm, high nuclear grade, diffuse architectural pattern) in common with all types of oncocytic tumors are outlined. The authors' proposed working rules for diagnostic categorization of oncocytic adrenocortical tumors are defined, with the presence of 1 major criterion indicating malignancy, 1 to 4 minor criteria indicating uncertain malignant potential (borderline), and the absence of all major and minor criteria indicative of benignancy. Using these criteria, the diagnosis of malignancy was straightforward in 3 of the 4 cases designated as oncocytic carcinoma (presence of at least 2 major criteria and all the minor criteria), while in 1 case the original diagnosis of benign oncocytoma was reversed to malignant following critical review of the original pathologic material after local tumor recurrence. Tumor recurrence occurred in 2 carcinomas at 8 and 20 months, respectively, and was followed in 1 case by the patient's death. The third patient expired at 6 months from unrelated causes, and the fourth patient is free of disease at the relatively short follow-up interval of 6 months. Regarding the 4 patients with borderline tumors, all are alive with no evidence of disease, with follow-up ranging from 10 to 61 months (mean 38.7 months). The 2 benign tumors have a follow-up of 25 and 30 months, respectively. Diagnostic difficulties are delineated and a complete review of the literature on this topic has also been performed.

Lateral Ventricle Tumors: Surgical Strategies According to Tumor Origin and Development— A Series of 72 Cases

OBJECTIVE:

Optimal surgical management in lateral ventricle tumors remains controversial. We conducted a retrospective study of patients with these lesions treated with a surgical strategy on the basis of tumor origin: primary or secondary ventricular and associated transependymal development.

METHODS:

A total of 72 patients underwent surgery for lateral ventricle tumors. The mean patient age was 39 years (range, 6 mo to 78 yr). Raised intracranial pressure occurred in 53% of patients, followed by mental disturbances or psychiatric symptoms (32%) and motor deficits (21%). The transcortical approach was used in 44 patients, and an interhemispheric approach was used in 28 patients; a transcallosal approach was used in 16 patients, and a parasplenial approach was used in 12 patients. Neuropsychological tests were performed in selected patients.

RESULTS:

Total resection was performed in 82% of patients. Sixty-five percent of tumors were benign and low-grade tumors. There was no surgical mortality, and the morbidity rate was 11%. Postoperative epilepsy (5.9%) was significantly increased in the transcortical group. The mean follow-up period was 55 months; 59% of patients achieved good recovery and moderate disability. In postoperative neuropsychological testing sessions, deficits in verbal memory were observed in six patients (8%). Final morbidity correlated well with preoperative clinical condition and pathological diagnosis.

CONCLUSION:

Lateral ventricle tumors can be treated best by careful selection of the approach according to tumor origin and development. Overall, the transcallosal approach is preferred, but in patients with transependymal growth or large primary or secondary ventricular tumors, the transcortical is a better option.

Novel somatic MEN1 gene alterations in sporadic primary hyperparathyroidism and correlation with clinical characteristics

Primary hyperparathyroidism (pHPT) is a common endocrine disease that in more than 95% of cases is sporadic and only in some cases is caused by inherited disorders, isolated or as part of multiple endocrine neoplasia (MEN1 and 2). Somatic mutations of MEN1 gene have also been described in sporadic parathyroid tumors. In our study, we examined the presence of alterations in MEN1 gene in a series of 39 patients who had undergone surgery for sporadic pHPT (35 with parathyroid adenoma or hyperplasia, 4 with a carcinoma). A genotype-phenotype correlation was also analysed. After DNA extraction from paraffin-embedded tissues, we amplified by PCR and sequenced the exons 2-10 of the MEN1 gene. Somatic MEN1 mutations were detected in 6 of the 35 patients with a benign parathyroid lesion examined (17.1%), whereas no alterations were found in the carcinomas. Four novel MEN1 gene mutations were identified as follows: one frameshift mutation (222insT, exon 2), one frameshift deletion (912delTA, exon 5), one in-frame deletion (835del18, exon 4) and one missense mutation (P291A, exon 6). In addition, one missense mutation (L89R, exon 2) and one nonsense mutation (Q536X, exon 10) were previously reported. Moreover, two polymorphisms were also found: one allele carried a R171Q polymorphism (1/39 tumors), while a D418D polymorphism (GAC/GAT) was found in 15 and 8 tumors in hetero (CT) and homozygosity (TT), respectively. In no case (mutations and/or polymorphisms) did we find a genotype-phenotype correlation. In conclusion, our data demonstrate the presence of somatic alterations of the MEN1 tumor suppressor gene in about one fifth of benign sporadic parathyroid tumors. The absence of a genotype-phenotype correlation, however, suggests the involvement of other genetic/epigenetic factors for the full expression of the disease.

Endometrioid carcinoma of the fallopian tube resembling a female adnexal tumor of probable wolffian origin

Endometrioid carcinoma of the fallopian tube resembling a female adnexal tumor of probable wolffian origin (FATWO) is a rare, recently delineated, low-grade carcinoma that may be confused with both FATWO and high-grade carcinoma. Only about 20 cases have been reported so far, but it probably represents almost half of the endometrioid carcinomas of the fallopian tube. It has a better prognosis than conventional tubal endometrioid and serous carcinomas. Macroscopically, the tumors form a small, solid, polypoid mass that is usually confined within the tube. Microscopically, the tumors are characterized by proliferations of spindle cells in whorls and closely packed confluent elongated glands with focal tubular, sieve-like, and papillary structures. Unlike FATWO, this variant of endometrioid carcinoma exhibits focal squamous differentiation, intraluminal mucin, mild to moderate nuclear atypia, and occasional mitosis. Unlike FATWO, tumor cells are negative for inhibin-alpha and calretinin.

Mixed epithelial and stromal tumors of the kidney. A report of 22 cases

Mixed epithelial and stromal tumor of the kidney (MESTK) is a recently described subset of renal neoplasm that tends to occur in middle-aged and older women and is characterized by a distinctive histological appearance. To further characterize this lesion, we report the clinicopathological and immunohistochemical features of 22 additional cases from our institutional files. Grossly, the tumors ranged in size from 1 cm to 14 cm (mean 6.7 cm), were well circumscribed but unencapsulated, and showed a cystic cut surface. The tumors were composed of a spindle cell proliferation that resembled ovarian stroma, as well as an epithelial component lining the cystic structures, which usually consisted of flat to hobnailed cells typical of collecting-duct epithelium. Areas displaying features of Mullerian differentiation were also documented in 6 cases, including epithelium of endometrioid, tubal, clear cell and squamous cell type as well as one case showing an architecture that closely resembled Mullerian adenofibroma and adenosarcoma. Follow-up in 14 patients (average 4.4 years) showed no evidence of recurrence or metastasis. We believe these tumors represent the renal counterpart of similar mixed epithelial and stromal neoplasms occurring in the biliary tract and pancreas, which is also characterized by cystic structures lined by epithelium, admixed with ovarian-type stroma. The differential diagnosis for these tumors includes cystic nephroma and cystic partially differentiated nephroblastoma, which we believe to represent clinically and morphologically distinct entities from MESTK. In particular, the distinction from cystic nephroma in adult male patients is emphasized, and two cases of this entity are included in the study for comparison.