Evaluating Mismatch Repair/Microsatellite Instability Status Using Cytology Effusion Specimens to Determine Eligibility for Immunotherapy

CONTEXT.—

The approval of pembrolizumab for treatment of patients with microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) advanced cancers has led to increased requests for MSI and/or MMR immunoperoxidase (IPOX) testing. Diagnoses for patients with advanced-stage cancer are frequently made from cytology specimens.

OBJECTIVE.—

To investigate the feasibility of using cell block (CB) preparations of effusions for MMR IPOX evaluation.

DESIGN.—

Surgical pathology cases of colorectal and endometrial carcinomas with known MMR/MSI status and matched effusions with available CBs were identified. Cell block sections were evaluated for adequacy and stained with MMR IPOX (MSH2, MSH6, MLH1, and PMS2). The CBs were reviewed, the number of tumor cells quantified, and MMR IPOX was interpreted as retained, lost, suboptimal, or noncontributory.

RESULTS.—

We identified 748 cases with MMR/MSI testing on surgical specimens having matched effusions. Of these, 131 cases (17.5%) had an available CB and 53 were deemed adequate for MMR IPOX staining. MMR IPOX results between effusion CBs and surgical pathology specimens were concordant in 45 of 53 (85%), inconclusive in 6 of 53 (11%), and discordant in 2 of 53 (4%) cases.

CONCLUSIONS.—

There was high concordance of MMR IPOX testing between cytologic and surgical specimens, with no false-positive and 2 false-negative CB results. Limited tumor cells, staining in cells indefinite as tumor, tumor staining heterogeneity, and lack of internal control staining were problematic in some cases. Our findings indicate that cytologic effusion specimens may be suitable substrates for MMR IPOX biomarker testing; however, inconclusive cases need to be interpreted with caution.

The value of a tiered cytology diagnostic reporting system in assessing the risk of malignancy in indeterminate serous effusions

BACKGROUND

The International System for Reporting Serous Fluid Cytopathology was recently proposed as a tiered structure to provide consistent reporting terminology for serous effusions. Because of the variation in reporting practices for indeterminate serous effusions, namely, the atypia of undetermined significance (AUS) and suspicious for malignancy (SFM) groups, the authors retrospectively reviewed cases in these 2 categories at their institution and determined the associated risk of malignancy (ROM).

METHODS

Pleural, peritoneal, and pericardial effusions that were reported as AUS or SFM over a 1-year period were reviewed, and their associated ROMs were calculated based on confirmation of malignancy by previous and/or subsequent fluid and/or tissue biopsy specimens from the same general location.

RESULTS

In total, 145 AUS and 98 SFM serous effusion cases were identified. The AUS category was used when the cells in question lacked the requisite quantitative (cell number) and/or qualitative (morphologic) features for a definitive diagnosis. Immunohistochemistry (IHC) or flow cytometry (FCM) was available in 15% of cases (n = 22) with inconclusive results. The ROM based on 69 cases with available follow-up results was 39%. In contrast, the SFM category demonstrated cells that were morphologically suspicious for malignancy but sparse, precluding IHC or FCM (n = 63; 64%) or yielding inconclusive results (n = 35; 36%). The ROM in the SFM category, based on follow-up results of 61 cases, was 64%.

CONCLUSIONS

The ROM for SFM was significantly higher than that for AUS (P < .01), supporting separate diagnostic categories for these 2 groups.

Case Report of Myeloid Sarcoma Masquerading as In-Transit Metastasis at a Previous Melanoma Site: Avoiding a Diagnostic Pitfall

Myeloid sarcoma is a rare extramedullary hematologic malignancy. Accurate and timely diagnosis may be challenging because myeloid sarcoma is known to mimic solid tumors, including hepatobiliary, nasopharyngeal, and breast carcinomas. We report a case of myeloid sarcoma that developed in the primary tumor lymphatic drainage field of a previously treated intermediate-thickness cutaneous melanoma, clinically and radiographically mimicking an in-transit metastasis, in a patient with myelodysplastic syndrome. The diagnosis of myeloid sarcoma was achieved after surgical excision of the mass and pathological examination that included extensive immunohistochemical studies. Awareness of such an unusual clinical presentation can help reduce diagnostic delay and ensure that adequate tissue is obtained for pathological examination and ancillary studies that are critical for accurate diagnosis and appropriate patient management.

Non-seminomatous germ cell tumor with bone metastasis only at diagnosis: A rare clinical presentation

Bone metastasis of non-seminomatous germ cell tumors (NSGCT) of the testes is a rare event and even more uncommon at initial presentation. Generally, bone lesions are discovered in the presence of concurrent retroperitoneal lymph node or visceral disease. However, in this case, a 37 years old male complaining of a growing testicular mass was found to have isolated bone metastasis with associated caudaequina syndrome without apparent abnormal findings on initial computed tomography (CT) scans. Continued neurologic symptoms prompted further evaluation with magnetic resonance imaging (MRI), which demonstrated multiple sites of bone metastasis without evidence of retroperitoneal lymph node or visceral organ involvement. This case represents a rare clinical presentation and disease manifestation of NSGCT.

A common complication of myelofibrosis presenting as a rare finding in cerebrospinal fluid cytology

Herein, we present a rare case of intracranial extramedullary hematopoiesis (EMH) diagnosed by cerebrospinal fluid (CSF) cytology and describe the clinical presentation, radiologic, and pathologic findings. A 65 year-old man with a history of progressing primary myelofibrosis was admitted for headaches and right facial numbness. A brain MRI revealed focal abnormalities that were suspicious for leptomeningeal involvement of acute leukemia. Cytologic examination of CSF demonstrated a hypercellular specimen composed of hematopoietic cells including few blasts, as well as maturing red blood cells and granulocytic cells. The integration of morphologic findings, peripheral blood and bone marrow counts, as well as flow cytometric analysis of CSF and bone marrow, excluded leptomeningeal involvement by leukemic blasts and helped establish the diagnosis of intracranial EMH. Inclusion of EMH in the differential diagnosis of intracranial pathology in patients with known conditions predisposing them to EMH is important because recognizing this rare event has implications for treatment and prognosis.

Pulmonary artery intimal sarcoma diagnosed using endobronchial ultrasound-guided transbronchial needle aspiration

Intimal sarcoma of the pulmonary artery is a rare intraluminal malignant neoplasm that has an aggressive biological behavior, and early diagnosis may improve patient outcome. We describe a case of pulmonary artery intimal sarcoma diagnosed on cytologic material obtained by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) biopsy with rapid on-site evaluation (ROSE). The aspirate showed loosely cohesive clusters of pleomorphic malignant spindled and epithelioid cells. An immunostain panel did not demonstrate any definitive mesenchymal or epithelial differentiation. The tumor's intraluminal origin was supported by radiographic imaging studies. Subsequently, the patient received preoperative chemotherapy and underwent tumor resection with reconstruction. This report describes the cytomorphologic features of this rare intravascular tumor and demonstrates how EBUS-TBNA with ROSE was instrumental in obtaining optimal cytologic sampling for ancillary studies, thus expediting the management.

Fine-needle aspiration diagnosis of lymphomas with signet ring cell features: potential pitfalls and solutions

BACKGROUND

Lymphoma with signet ring cell features (LSF) is a rare morphologic variant of non-Hodgkin lymphoma. Although it has been well documented in the surgical pathology literature, to the best of the authors's knowledge, the features of LSF in fine-needle aspiration (FNA) samples have rarely been reported. An accurate cytologic diagnosis of LSF is of important therapeutic significance.

METHODS

The authors retrospectively reviewed 7 FNA cases of LSF for cytologic features, ancillary studies, corresponding histologic findings, and the patients' clinical and radiologic information to illustrate the diagnostic clues and potential pitfalls.

RESULTS

The final diagnoses, based on a multidisciplinary approach, were follicular lymphoma (5 patients), large B-cell lymphoma of follicular center cell origin (1 patient), and low-grade B-cell lymphoma with plasmacytoid features (1 patient). FNAs were obtained from both lymph node and extranodal sites. Common cytologic features included various percentages of signet ring cells in a background of nonvacuolated lymphomatous cells, lymphoglandular bodies, and cytoplasmic rings. The majority of signet ring cells contained a single, large, clear intracytoplasmic vacuole that pushed the nucleus laterally whereas fewer cells contained ≥ 2 vacuoles that indented the nucleus into a scalloped or stellate configuration. These cells resemble, to some degree, other lesions with signet ring cell features. One of the diagnostic clues of LSF was the similarity in nuclear details between signet ring cells and surrounding nonvacuolated lymphoid cells.

CONCLUSIONS

Familiarity with cytologic features, correlation with clinical/radiologic information, and ancillary studies are important for an accurate diagnosis of LSF and for distinguishing it from other lesions with signet ring cell features in FNA samples.

Fine-needle aspiration cytology of sclerosing adenosis of the breast: a retrospective review of cytologic features in conjunction with corresponding histologic features and radiologic findings

We retrospectively reviewed 25 fine-needle aspiration cases of sclerosing adenosis of the breast in conjunction with histologic features of the paired core-needle biopsy and radiologic findings. The original cytologic diagnoses were benign (n = 19), focally atypical (n = 3), and suspicious for carcinoma (n = 3). The frequent features, although not specific, were low-to-moderate cellularity, bland epithelial cells that focally formed cohesive groups/tubules or occasionally discohesive clusters or individual cells, and fragments of dense fibrous stroma. Some tubules had an angulated configuration. Myoepithelial cells were present in all cases but were scant or absent in small epithelial groups. These cytologic features closely reflected the histologic appearances (ie, compressed and attenuated tubules and sclerotic stroma), but may cause overinterpretation on cytologic smears, especially when angulated tubules, discohesive or individual epithelial cells, scanty myoepithelial cells, and nuclear atypia are noted concurrently. Familiarity with its cytologic features may prevent false-positive diagnosis. Histologic confirmation is recommended for difficult cases.

Peritoneal washing cytology in patients with BRCA1 or BRCA2 mutations undergoing risk-reducing salpingo-oophorectomies: a 10-year experience and reappraisal of its clinical utility

OBJECTIVE

To evaluate the utility of peritoneal washing cytology (PWC) for detecting occult primary peritoneal carcinoma in patients with BRCA1 or BRCA2 mutations, we reviewed PWCs obtained during risk-reducing salpingo-oophorectomy (RRSO) from 117 patients at our institution and correlated the results with surgical pathology findings.

METHODS

Records of 128 PWCs from 125 patients with BRCA1 or BRCA2 mutations undergoing RRSO at MD Anderson Cancer Center between 2000 and 2010 were obtained. Slides were available for review for 119 PWCs from 117 patients (2 patients had 2 PWCs each). Cytopathologists, blinded to the RRSO histopathologic diagnoses, categorized the PWCs as benign, atypical, suspicious for malignancy, or malignant. These results were correlated with the RRSO histopathologic diagnoses.

RESULTS

PWCs from 113 patients were benign. Of the remaining 4 patients, 2 had PWCs classified as atypical, 1 as suspicious for malignancy, and 1 as malignant. The corresponding RRSO histopathologic findings of the 2 atypical PWCs showed endosalpingiosis and cystadenofibroma in one case and showed no abnormalities in the other case. Both patients with suspicious or malignant PWCs, indicating the possibility of occult peritoneal carcinoma, had RRSO histopathologic diagnoses of endometriosis and endosalpingiosis. Nine patients had abnormal tubal or ovarian histologic findings, but all 9 of these patients had benign PWCs.

CONCLUSION

PWC has the potential to detect occult peritoneal carcinoma in patients with BRCA1 or BRCA2 mutations. The clinical significance of a positive PWC without abnormal RRSO histology remains unclear and will require long-term follow-up for determination.

Histiocytoid eccrine sweat gland carcinoma of the eyelid: report of a case

This report describes the 12th documented case of histiocytoid, diffuse or signet-ring cell eccrine sweat gland carcinoma of the eyelid, a rare neoplasm that characteristically affects older men and mimics distant metastasis. Clinically, the patient was thought to have a colonic metastasis. Histologically, the neoplasm comprised sheets and cords of polygonal, eosinophilic cells, with dispersed larger, rounded single cells resembling histiocytes, and cells with cytoplasmic lumina or a signet-ring appearance. Occasional duct formation was also seen. The features were reminiscent of both the histiocytoid and lobular variants of breast carcinoma. Ultrastructurally, the presence of nonintestinal type microvilli with a length : width ratio in excess of 16 were consistent with an eccrine origin, but also raised the possibility of metastatic mesothelioma. However, a metastatic lesion was excluded by clinical and imaging investigations. There has been no recurrence 3 years after primary excision.

Intra-osseous soft tissue perineurioma of the inferior alveolar nerve

This report describes an intra-osseous perineurioma affecting the inferior alveolar nerve, the second at this site, of a 53-year-old man. It produced a well defined, partially corticated, round radiolucency associated with resorption of the root apices of 36 and 37. Histology showed a circumscribed, partially encapsulated cellular tumour composed of bland spindle cells with undulating nuclei and indistinct cell membranes arranged in interlacing fascicles. The tumour was strongly positive for epithelial membrane antigen, collagen IV and laminin, with only scattered S100-positive cells and lack of CD34 expression. Electron microscopy showed elongated cells with continuous external laminae of basement membrane-like material, subplasmalemmal densities, desmosome-like junctions, and variable numbers of micropinocytotic vesicles. The lesion was surgically excised and in 9 months there has been no recurrence.

Effects of elevated carbon dioxide and ozone on the growth and yield of potatoes (Solanum tuberosum) grown in open-top chambers

Potato (Solanum tuberosum cv. Bintje) was grown in open-top chambers under three carbon dioxide (ambient and seasonal mean concentrations of 550 and 680 mumol mol-1 CO2) and two ozone concentrations (ambient and an 8 h day-1 seasonal mean of 50 nmol mol-1 O3) between emergence and final harvest. Periodic non-destructive measurements were made and destructive harvests were carried out at three key developmental stages (24, 49 and 101 days after emergence) to establish effects on growth and tuber yield. Season-long exposure to elevated O3 reduced above-ground dry weight at final harvest by 8.4% (P < 0.05), but did not affect tuber yields. There was no significant interaction between CO2 and O3 for any of the growth and yield variables examined. Non-destructive analyses revealed no significant effect of elevated CO2 on plant height, leaf number or green leaf area ratio. However, destructive harvests at tuber initiation and 500 degrees Cd after emergence showed that above-ground dry weight (8 and 7% respectively) and tuber yield (88 and 44%) were significantly increased (P < 0.05) in the 550 mumol mol-1 CO2 treatment. Responses to 550 and 680 mumol mol-1 CO2 were not significantly different for most parameters examined, suggesting the existence of an upper limit to the beneficial influence of CO2 enrichment. Significant effects on above-ground dry weight and tuber yield were no longer apparent at final harvest, although tuber numbers were increased (P < 0.05) under elevated CO2, particularly in the smaller size categories. The results show that the O3 treatment imposed was insufficient to reduce tuber yields and that, although elevated CO2 enhanced crop growth during the early stages of the season, this beneficial effect was not sustained to maturity.

Baseline hemoglobin as a predictor of risk of transfusion and response to Epoetin alfa in orthopedic surgery patients

A multicenter, double-blind, placebo-controlled, parallel-group study was undertaken to determine whether Epoetin alfa can reduce perioperative transfusion requirements. Twenty-six medical centers enrolled 316 patients who were scheduled for major orthopedic surgery and were expected to require > or = 2 units of blood. Patients were stratified according to baseline hemoglobin levels and randomly assigned to receive either Epoetin alfa (300 IU/kg or 100 IU/kg) or placebo for 15 consecutive days starting 10 days prior to, on the day of, and for 4 days after surgery. Epoetin alfa (300 IU/kg) resulted in significantly less exposure to allogeneic blood transfusion compared with placebo (16%) versus 45%) in patients whose baseline hemoglobin level was > 10 to < or = 13 g/dL (P = 0.024). Mean number of units transfused per patient was also lower among those treated with Epoetin alfa (overall, P = 0.027). Epoetin alfa was safe and well tolerated in this population.

Arthroscopic treatment of osteoarthritis of the knee: a prospective, randomized, placebo-controlled trial. Results of a pilot study

The reasons why many patients seemingly benefit from arthroscopic treatment of osteoarthritis of the knee remain obscure. The purpose of this pilot study was to determine if a placebo effect might play a role in arthroscopic treatment of this condition. After giving full informed consent, including full knowledge of the possibility and nature of a placebo surgery, five subjects were randomized to a placebo arthroscopy group, three subjects were randomized to an arthroscopic lavage group, and two subjects were randomized to a standard arthroscopic debridement group. The physicians performing the postoperative assessment and the patients remained blinded as to treatment. Patients who received the placebo surgery reported decreased frequency, intensity, and duration of knee pain. They also thought that the procedure was worthwhile and would recommend it to family and friends. Thus, there may be a significant placebo effect for arthroscopic treatment of osteoarthritis of the knee. The small numbers in this preliminary study preclude a valid statistical analysis, and no conclusions can be drawn regarding the superiority of one treatment over another. A larger study is needed to evaluate fully the efficacy of an arthroscopic procedure for this condition and to decide if it is reasonable to expend health care resources for this treatment; the larger study should include a placebo control group.

Inflammatory pseudotumor of the spleen. Report of two cases with a review of the literature

This study reports two cases of inflammatory pseudotumor of the spleen. The first case was a 57-year-old woman in whom the splenic mass was an incidental finding during evaluation for an acute abdomen due to a perforated, lithiasic gallbladder. The mass in the spleen measured 12.7 cm in greatest dimension. The second case was of a 46-year-old woman with a palpable, left upper quadrant mass. A computed tomography scan revealed a splenic mass and the spleen was removed. The mass measured 12 cm in greatest dimension. In a review of the literature, 13 examples of splenic inflammatory pseudotumor were reported. The age range was 19 to 75 years, with a median age of 50 years. The splenic lesions were either discovered incidentally or manifested by left upper quadrant discomfort and/or mass. Inflammatory pseudotumor of the spleen, although rare, is being increasingly recognized and should be considered in the differential diagnosis of mass lesions of the spleen.

Primary angiosarcoma of the cuboidal bone: a case report

Primary angiosarcoma of bone is a rare neoplasm. The unique cytomorphologic and ultrastructural aspects of a primary angiosarcoma of the cuboid bone diagnosed by fine-needle aspiration are presented. Smears and cell block preparations revealed single and clustered large, pleomorphic, and spindle-shaped cells with a markedly hemorrhagic background. Electron microscopy revealed characteristic features of endothelial cells including rare Weibel-Palade bodies. The clinical, cytologic, histologic, and ultrastructural aspects of the case are discussed.

Endometrial tissue in myometrial vessels not associated with menstruation

The presence of endometrial tissue in myometrial vessels has been described in the literature primarily in association with the menstrual period. We reviewed 277 hysterectomy specimens to assess the frequency of endometrial tissue in myometrial vessels in the uteri of nonmenstruating women. Intravascular endometrial tissue was observed in 14 cases, all of which showed extensive adenomyosis usually present in multiple foci. None of the uteri without adenomyosis showed intravascular endometrial tissue. In foci of adenomyosis, the intimate relationship of endometrial tissue and vessels might be explained by the possible origin of endometrial tissue from uncommitted perivascular cells, a possibility that is supported by our failure to demonstrate a connection between the foci of adenomyosis and endometrium in serial sections. When the uncommitted perivascular cells proliferate, they may impinge on endothelially intact vascular lumina and later become intraluminal. Pathologists should be aware of this phenomenon associated with adenomyosis to avoid interpreting the cells within vessels as being neoplastic.

Carcinoid metastatic to breast diagnosed by fine-needle aspiration biopsy

We report a patient in whom fine-needle aspiration biopsy of a breast mass, clinically suspected to be a mammary adenocarcinoma, established the diagnosis of a carcinoid metastatic to breast. The aspirate smears resembled a primary breast carcinoma; however, subtle cytomorphologic differences were present. Ultrastructural and immunohistochemical studies of the aspirate material confirmed the diagnosis of metastatic carcinoid.

Solitary histoplasmoma of the thalamus: case report and literature review

Only nine cases of solitary thalamic abscess have been reported. All were of bacterial origin, and three were successfully treated by surgical drainage and antibiotic therapy. The authors present the history of a patient with a histoplasmoma of the thalamus. As is often the case with solitary thalamic lesions, this lesion was initially assumed to be a tumor and was first treated with radiotherapy. Despite the sensitive location of the lesion, tissue diagnosis and decompression was safely accomplished with the aid of ultrasonic localization. Appropriate antifungal treatment was given, and the patient made a good recovery.

Cardiac myxomas. An immunohistochemical study using endothelial, histiocytic, and smooth-muscle cell markers

Previous immunohistochemical studies of cardiac myxomas are few in number, limited in scope and, in part, discrepant. We studied the immunoreactivity of five cardiac myxomas for factor VIII-related antigen, Ulex europaeus agglutinin I, smooth-muscle myosin, alpha 1-antitrypsin, and alpha 1-antichymotrypsin. Positive staining was present in all five tumors with each cell marker used, but varied according to the area of tumor examined. The result of this study provides further evidence of the cellular heterogeneity in these tumors that probably originate by differentiation of multipotential mesenchymal cells.

Clear cell variant of medullary carcinoma of the thyroid

A previously unreported clear cell variant of medullary thyroid carcinoma is described. This histologic appearance was observed in sections from both the primary thyroid tumor and a vertebral metastasis. This variant merits recognition because it may be confused with a variety of other tumors occurring in the thyroid that contain cells with optically clear cytoplasm. Immunohistochemical and ultrastructural studies can be helpful in establishing the diagnosis of these tumors.

The clinical application of electron microscopy and the heterologous ova penetration test to the assessment of spermatozoa from infertile men

Ultrastructural studies of spermatozoa from men whose spermatozoa repeatedly had shown poor motility demonstrated an increase in morphological abnormalities. This was considered significant in the 8 men in whom all of the spermatozoa were abnornmal and probably significant in those where more than 90% were abnormal (9 men). Spermatozoa from 15 fertile men adhered to and penetrated 60% of hamster oocytes, whereas those from infertile men, with both normal and poor semen quality, failed to adhere or penetrate. The heterologous sperm penetration test offers a new approach to the assessment of semen quality in infertile men.

Testicular testosterone concentration, interstitial cell density and spermatogenesis in infertile men

The concentration of testosterone was estimated in testicular biopsies taken from infertile men under general anaesthesia and was found to vary between 0.77 and 9.87 nmol/g wet tissue (median 3.41 nmol/g). Spermatogenesis was assessed by the Johnsen scoring technique but there was no evidence of a deficiency of intratesticular testosterone being associated with dysfunction of the seminiferous tubules. Similarly, there was no direct relationship with testicular size, clinical diagnosis, or the concentration of testosterone found in peripheral plasma taken at the same time as the testicular biopsy. These negative findings were not explained by variation in the volume densities of the Leydig cells assessed in 10 biopsies selected to the representative of the range of testosterone concentrations found in entire series. A retrospective comparison between the concentration of testosterone in peripheral plasma at the time of surgery and the available preoperative levels found in 10 patients provided further evidence for the previously reported lowering of testosterone levels by general anaesthesia. It is suggested that future studies of testicular androgens should be conducted on tissue obtained under local anaesthesia in order to eliminate this effect.