130
Correspondence
M. Roy*, D. Jain*, S. Bakhshi†, S. Mathur* and V. K. Iyer* *Department of Pathology, and † Department of Medical Oncology, All India Institute of Medical Sciences, New Delhi, India References 1. William CL, Busque L, Griffith BB et al. Langerhans’-cell histiocytosis (histiocytosis X) – a clonal proliferative disease. N Engl J Med 1994;331:154–60. 2. Patten DK, Wani Z, Tolley N. Solitary Langerhans histiocytosis of the thyroid gland: a case report and literature review. Head Neck Pathol 2012;6:279–89. 3. Pusztaszeri MP, Sauder KJ, Cibas ES, Faquin WC. Fineneedle aspiration of primary Langerhans cell histiocytosis of the thyroid gland, a potential mimic of papillary thyroid carcinoma. Acta Cytol 2013;57:406–12. 4. Wohlschlaeger J, Ebert S, Sheu SY, Schmid KW, Totsch M. Immunocytochemical investigation of langerin (CD207) is a valuable adjunct in the cytological diagnosis of Langerhans cell histiocytosis of the thyroid. Pathol Res Pract 2009;205:433–6. 5. Howarth DM, Gilchrist GS, Mullan BP et al. Langerhans cell histiocytosis: diagnosis, natural history, management and outcome. Cancer 1999;85:2278–90.
FNA cytology revealing Langerhans cell histiocytosis and papillary thyroid carcinoma DOI:10.1111/cyt.12141
Dear Editor, Langerhans cell histiocytosis (LCH) is a rare disorder of unknown origin characterized by infiltration of the involved tissues by large numbers of Langerhans cells, often organized into granulomas. LCH can affect any organ of the body, but thyroid involvement is rare, with 65 described cases.1 Historically, the disease was confirmed by showing Birbeck granules by electron microscopy, but currently the diagnosis is based on immunostaining with CD1a and/or langerin.2 We describe a case of LCH associated with papillary thyroid carcinoma (PTC) demonstrated on liquid-based fine needle aspiration (FNA) cytology with immunocytochemistry (ICC). A 52-year-old woman presented with severe multisystem LCH, with skin, lung and pituitary involveCorrespondence: B. Cochand-Priollet, Department of Pathology, Lariboisiere Hospital-University Paris Diderot, Paris, France Tel.: +33 01 49 95 83 30; Fax: +33 01 49 95 85 36; E-mail: [email protected]
ment, having been treated with vinblastine over several years with partial response. Before the initiation of cladribine as second-line treatment, a positron emission tomography (PET) scan was performed which showed a generalized hypermetabolic thyroid. Ultrasound imaging revealed an echoic 21-mm-diameter nodule in the right lobe. The patient had no complaints, although hormonal evaluation revealed peripheral hypothyroidism. FNA of the thyroid, using a 25-gauge needle, was carried out in order to classify the lesion. The ThinPrep Hologic® (Hologic Inc., Marlborough, MA, USA) technique was used, giving us one Papanicolaou-stained slide. ICC was performed on additional slides using a Benchmark Ventana autostainer with CD1a (undiluted; Beckman Coulter O10, Marseille, France), cytokeratin 19 (CK19; dilution 1 : 10; Novocastra b170, Newcastle, UK) and human mesothelial cell marker 1 (HBME1; dilution 1 : 50; Dako, Glostrup, Denmark) antibodies. The FNA cytology was highly cellular, contained some watery colloid, and showed two distinct cell populations: the first consisted of monomorphic non-cohesive cells, with large and slightly basophilic cytoplasm and a few irregular/grooved nuclei (Figure 1a); the second consisted of a large monolayer or three-dimensional sheets of cuboidal cells, some with atypical grooved and elongated nuclei (Figure 1b). The latter suggested PTC, but was mixed with some normal epithelial cells and the required criteria were not all present. Furthermore, the cells were mixed with various inflammatory cells, mainly lymphocytes and neutrophils. No eosinophils were seen, perhaps as a result of Papanicolaou staining. ICC with CD1a showed strong staining of the isolated monomorphic cells, leading to the diagnosis of LCH thyroid involvement (Figure 1c). To further assess the malignancy of the second population, we performed HBME1 and CK19 ICC: HBME1 was strongly expressed in more than 90% of the cuboidal atypical cells, but CK19 was expressed in less than 70% of these cells; the immunostaining was rendered as ‘indeterminate’. According to the Bethesda terminology, the final diagnosis was suspicious for malignancy (suspicious for PTC) and other (LCH involvement). The patient underwent a right hemithyroidectomy. A 2-cm-wide papillary carcinoma without capsular invasion, classified as pT1b in the TNM system, was found in the right lobe, diagnosed on frozen section and confirmed on paraffin-embedded slides (Figure 1d). A thyroidectomy with cervical lymph node © 2014 John Wiley & Sons Ltd Cytopathology 2014, 26, 126–133
Correspondence
(a)
(b)
(c)
(d)
Figure 1. (a–c) Fine needle aspiration cytology: (a) isolated monomorphic cells with plentiful slightly basophilic cytoplasm and irregular nuclei (Papanicolaou 9600); (b) three-dimensional clusters of cuboidal cells with mild to moderate nuclear abnormalities, suggesting papillary carcinoma mixed with isolated cells (Papanicolaou 9600); (c) immunostaining of liquidbased cytology with CD1a showed strong staining of these isolated cells. (d) Histological section: Langerhans cell infiltration in the thyroid gland with papillary features and some nuclear atypia, confirmed as papillary thyroid carcinoma (haematoxylin and eosin 9200).
dissection was performed, revealing neither additional tumour nor lymph node metastases. LCH was confirmed on histology and ICC with CD1a (Beckman Coulter O10) and S100 protein (Dako S100 poly). The patient underwent radioactive iodine therapy for the papillary carcinoma and cladribine perfusions for the LCH. Eighteen months later, the LCH lesions had obviously decreased and there was no cancer recurrence. Molecular studies have shown that the papillary carcinoma was positive for the BRAF V600E mutation, but not the LCH component. Thyroid involvement in LCH is rare, as is its association with PTC. LCH in the thyroid occurs mostly in adults with a slight female predominance (sex ratio 1.4 : 1). As in our case, the diagnosis of LCH is often already known, with a number of patients suffering from diabetes insipidus (pituitary involvement). Patients present with a diffusely enlarged or nodular thyroid, but few symptoms. Thyroid hormone status is variable, with most patients being euthyroid. FNA cytological diagnosis is very difficult as Langerhans cells may be confused with many other entities, such as lymphoma, lymphocytic thyroiditis or undifferentiated carcinoma. Nevertheless, a close and cautious analysis of these cells renders them recognizable: lymphoma cells usually have more basophilic cytoplasm than LCH cells and the lymphoid component of lymphocytic thyroiditis is more pleomorphic; undifferentiated carcinoma shows more nuclear atypia and, occasionally, some cellular cohesion. The mixed inflammatory cells, with the characteristic infiltration by eosinophils, can be helpful, as well as ICC with lymphocyte markers or CD1a in an appropriate clinical setting. The association of thyroid LCH involvement with papillary carcinoma diagnosed on cytology was first described by Goldstein and Layfield in 19913 and © 2014 John Wiley & Sons Ltd Cytopathology 2014, 26, 126–133
then by others.2,4,5 LCH is known to be associated with other neoplasms, such as lymphoma, leukaemia or lung cancer,6 but the association with PTC remains rare and unclear, as there have only been a few reported cases. However, a recent study5 showed an increased presence of CD1a-positive dendritic cells in PTC. In conclusion, LCH thyroid involvement is rare, but the diagnosis is possible based on a representative highly cellular cytology sample, close examination and correlation with clinical data. Surgical removal seems to be the gold standard treatment for isolated LCH, whereas disseminated disease requires systemic therapy. Associated PTC may require further treatment, such as iodine therapy, but there are no standard recommendations. M. Bucau*, H. Dahan†, V. Meignin‡, M.-E. Toubert§, A. Tazi¶ and B. Cochand-Priollet* *Department of Pathology, †Radiology, Lariboisiere Hospital, ‡Department of Pathology, §Nuclear Medicine and ¶Respiratory Department, Reference Center for Langerhans Cell Histiocytosis, INSERM UMR 717, St. Louis Hospital-University Paris Diderot, Paris, France References 1. Patten DK, Wani Z, Tolley N. Solitary Langerhans histiocytosis of the thyroid gland: a case report and literature review. Head Neck Pathol 2011;6:279–89. 2. Wohlschlaeger J, Ebert S, Sheu S-Y, Schmid KW, T€ otsch M. Immunocytochemical investigation of Langerin (CD207) is a valuable adjunct in the cytological diagnosis of Langerhans cell histiocytosis of the thyroid. Pathol Res Pract 2009;205:433–6. 3. Goldstein N, Layfield LJ. Thyromegaly secondary to simultaneous papillary carcinoma and histiocytosis X. Report of a case and review of the literature. Acta Cytol 1991;35:422–6.
131
132
Correspondence
4. Pusztaszeri MP, Sauder KJ, Cibas ES, Faquin WC. Fineneedle aspiration of primary Langerhans cell histiocytosis of the thyroid gland, a potential mimic of papillary thyroid carcinoma. Acta Cytol 2013;57:406–12. 5. Pusztaszeri MP, Sadow PM, Faquin WC. Association of CD1a-positive dendritic cells with papillary thyroid carcinoma in thyroid fine-needle aspirations. Cancer Cytopathol 2013;121:206–13. 6. Egeler RM, Neglia JP, Aric M o et al. The relation of Langerhans cell histiocytosis to acute leukemia, lymphomas, and other solid tumors. The LCH-Malignancy Study Group of the Histiocyte Society. Hematol Oncol Clin North Am 1998;12:369–78.
Report of a case emphasizing the clinical utility of fine needle aspiration cytology in the diagnosis of histoid leprosy DOI:10.1111/cyt.12144
Dear Editor, There has been a significant literature on the role of fine needle aspiration cytology (FNAC) in the diagnosis of leprotic lesions, such as pure neuritic, reactionary and rare cases of skeletal leprosy.1,2 Histoid leprosy is a distinct and rare variant of leprosy manifesting with characteristic skin lesions, histopathological features and bacterial morphology.3 Owing to the lack of obvious lymphocytic response, pathologically, it often mimics spindle cell tumours. The literature on the cytodiagnosis of histoid leprosy is rather sparse. Nonetheless, because of its characteristic cytomorphological presentation, it is easily diagnosable by FNAC.4 We report a case highlighting the clinical utility of FNAC in its diagnosis. A 55-year-old man presented with multiple asymptomatic papular and nodular lesions over the trunk and face of 2 years’ duration. Peripheral nerves were thickened. Slit-skin smear examination and biopsy of one of the cutaneous nodules confirmed the diagnosis of lepromatous leprosy with a bacteriological index of 6+. The patient was started on multidrug therapy for multibacillary leprosy. During the course of 5 months of therapy, he developed fresh, firm, 0.8 9 0.8-cm2 to 1.5 9 1.5-cm2 nodular lesions on the right hand (Figure 1a,b), Correspondence: N. Siddaraju, Professor of Pathology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry 605 006, India Tel.: +91-99-44426595; Fax: +91-0413-2272067; E-mail: [email protected]
which were suspected to be caused by erythema nodosum leprosum (ENL). The nodules were subjected to FNAC by the standard procedure. Air-dried and 95% ethanol-fixed smears were stained with routine May–Gr€ unwald–Giemsa (MGG) and Papanicolaou (Pap) stains. Fites stain was performed on one of the air-dried smears. The smears were highly cellular with tight clusters and fragments of spindle cells, in places arranged in a vague palisading manner and having foamy cytoplasm with distinct negative images. Fine vacuolation and negative images were also appreciated in the smear background of MGG smears (Figure 2a–c). No intervening stroma or obvious neutrophilic/lymphocytic infiltrate was seen within the spindle cell fragments, and the Fites stain was strongly positive, corresponding to the negative images (Figure 2d). A cytological diagnosis of ‘histoid leprosy’ was rendered. The term ‘histoid leprosy’ was originally coined in 1963 by Wade.5 Most commonly, it affects multibacillary patients who are on irregular and inadequate dapsone therapy; however, it can also arise de novo.3 This distinct entity received adequate attention only after Sehgal et al.6 documented its immunological profile in 1985. Histoid leprosy is said to be the result of an altered growth pattern of Mycobacterium leprae, caused by the loss of immunity in a localized area. Nodules of histoid leprosy are often confused with lepromatous nodules, and cytomorphology can play a substantial role in distinguishing between the two.4 There are only rare studies and reports describing the cytomorphological features of histoid leprosy.3,4 Two patterns of cytological presentation have been described.4 The most common presentation is a high cell yield3,4 with multilayer palisades of spindle-shaped histiocytes on an endothelial vascular core.4 The spindly macrophages show a dense
(a)
(b)
Figure 1. Clinical photographs showing nodules on the right wrist (a) and hand (b). © 2014 John Wiley & Sons Ltd Cytopathology 2014, 26, 126–133
Copyright of Cytopathology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
Correspondence
M. Roy*, D. Jain*, S. Bakhshi†, S. Mathur* and V. K. Iyer* *Department of Pathology, and † Department of Medical Oncology, All India Institute of Medical Sciences, New Delhi, India References 1. William CL, Busque L, Griffith BB et al. Langerhans’-cell histiocytosis (histiocytosis X) – a clonal proliferative disease. N Engl J Med 1994;331:154–60. 2. Patten DK, Wani Z, Tolley N. Solitary Langerhans histiocytosis of the thyroid gland: a case report and literature review. Head Neck Pathol 2012;6:279–89. 3. Pusztaszeri MP, Sauder KJ, Cibas ES, Faquin WC. Fineneedle aspiration of primary Langerhans cell histiocytosis of the thyroid gland, a potential mimic of papillary thyroid carcinoma. Acta Cytol 2013;57:406–12. 4. Wohlschlaeger J, Ebert S, Sheu SY, Schmid KW, Totsch M. Immunocytochemical investigation of langerin (CD207) is a valuable adjunct in the cytological diagnosis of Langerhans cell histiocytosis of the thyroid. Pathol Res Pract 2009;205:433–6. 5. Howarth DM, Gilchrist GS, Mullan BP et al. Langerhans cell histiocytosis: diagnosis, natural history, management and outcome. Cancer 1999;85:2278–90.
FNA cytology revealing Langerhans cell histiocytosis and papillary thyroid carcinoma DOI:10.1111/cyt.12141
Dear Editor, Langerhans cell histiocytosis (LCH) is a rare disorder of unknown origin characterized by infiltration of the involved tissues by large numbers of Langerhans cells, often organized into granulomas. LCH can affect any organ of the body, but thyroid involvement is rare, with 65 described cases.1 Historically, the disease was confirmed by showing Birbeck granules by electron microscopy, but currently the diagnosis is based on immunostaining with CD1a and/or langerin.2 We describe a case of LCH associated with papillary thyroid carcinoma (PTC) demonstrated on liquid-based fine needle aspiration (FNA) cytology with immunocytochemistry (ICC). A 52-year-old woman presented with severe multisystem LCH, with skin, lung and pituitary involveCorrespondence: B. Cochand-Priollet, Department of Pathology, Lariboisiere Hospital-University Paris Diderot, Paris, France Tel.: +33 01 49 95 83 30; Fax: +33 01 49 95 85 36; E-mail: [email protected]
ment, having been treated with vinblastine over several years with partial response. Before the initiation of cladribine as second-line treatment, a positron emission tomography (PET) scan was performed which showed a generalized hypermetabolic thyroid. Ultrasound imaging revealed an echoic 21-mm-diameter nodule in the right lobe. The patient had no complaints, although hormonal evaluation revealed peripheral hypothyroidism. FNA of the thyroid, using a 25-gauge needle, was carried out in order to classify the lesion. The ThinPrep Hologic® (Hologic Inc., Marlborough, MA, USA) technique was used, giving us one Papanicolaou-stained slide. ICC was performed on additional slides using a Benchmark Ventana autostainer with CD1a (undiluted; Beckman Coulter O10, Marseille, France), cytokeratin 19 (CK19; dilution 1 : 10; Novocastra b170, Newcastle, UK) and human mesothelial cell marker 1 (HBME1; dilution 1 : 50; Dako, Glostrup, Denmark) antibodies. The FNA cytology was highly cellular, contained some watery colloid, and showed two distinct cell populations: the first consisted of monomorphic non-cohesive cells, with large and slightly basophilic cytoplasm and a few irregular/grooved nuclei (Figure 1a); the second consisted of a large monolayer or three-dimensional sheets of cuboidal cells, some with atypical grooved and elongated nuclei (Figure 1b). The latter suggested PTC, but was mixed with some normal epithelial cells and the required criteria were not all present. Furthermore, the cells were mixed with various inflammatory cells, mainly lymphocytes and neutrophils. No eosinophils were seen, perhaps as a result of Papanicolaou staining. ICC with CD1a showed strong staining of the isolated monomorphic cells, leading to the diagnosis of LCH thyroid involvement (Figure 1c). To further assess the malignancy of the second population, we performed HBME1 and CK19 ICC: HBME1 was strongly expressed in more than 90% of the cuboidal atypical cells, but CK19 was expressed in less than 70% of these cells; the immunostaining was rendered as ‘indeterminate’. According to the Bethesda terminology, the final diagnosis was suspicious for malignancy (suspicious for PTC) and other (LCH involvement). The patient underwent a right hemithyroidectomy. A 2-cm-wide papillary carcinoma without capsular invasion, classified as pT1b in the TNM system, was found in the right lobe, diagnosed on frozen section and confirmed on paraffin-embedded slides (Figure 1d). A thyroidectomy with cervical lymph node © 2014 John Wiley & Sons Ltd Cytopathology 2014, 26, 126–133
Correspondence
(a)
(b)
(c)
(d)
Figure 1. (a–c) Fine needle aspiration cytology: (a) isolated monomorphic cells with plentiful slightly basophilic cytoplasm and irregular nuclei (Papanicolaou 9600); (b) three-dimensional clusters of cuboidal cells with mild to moderate nuclear abnormalities, suggesting papillary carcinoma mixed with isolated cells (Papanicolaou 9600); (c) immunostaining of liquidbased cytology with CD1a showed strong staining of these isolated cells. (d) Histological section: Langerhans cell infiltration in the thyroid gland with papillary features and some nuclear atypia, confirmed as papillary thyroid carcinoma (haematoxylin and eosin 9200).
dissection was performed, revealing neither additional tumour nor lymph node metastases. LCH was confirmed on histology and ICC with CD1a (Beckman Coulter O10) and S100 protein (Dako S100 poly). The patient underwent radioactive iodine therapy for the papillary carcinoma and cladribine perfusions for the LCH. Eighteen months later, the LCH lesions had obviously decreased and there was no cancer recurrence. Molecular studies have shown that the papillary carcinoma was positive for the BRAF V600E mutation, but not the LCH component. Thyroid involvement in LCH is rare, as is its association with PTC. LCH in the thyroid occurs mostly in adults with a slight female predominance (sex ratio 1.4 : 1). As in our case, the diagnosis of LCH is often already known, with a number of patients suffering from diabetes insipidus (pituitary involvement). Patients present with a diffusely enlarged or nodular thyroid, but few symptoms. Thyroid hormone status is variable, with most patients being euthyroid. FNA cytological diagnosis is very difficult as Langerhans cells may be confused with many other entities, such as lymphoma, lymphocytic thyroiditis or undifferentiated carcinoma. Nevertheless, a close and cautious analysis of these cells renders them recognizable: lymphoma cells usually have more basophilic cytoplasm than LCH cells and the lymphoid component of lymphocytic thyroiditis is more pleomorphic; undifferentiated carcinoma shows more nuclear atypia and, occasionally, some cellular cohesion. The mixed inflammatory cells, with the characteristic infiltration by eosinophils, can be helpful, as well as ICC with lymphocyte markers or CD1a in an appropriate clinical setting. The association of thyroid LCH involvement with papillary carcinoma diagnosed on cytology was first described by Goldstein and Layfield in 19913 and © 2014 John Wiley & Sons Ltd Cytopathology 2014, 26, 126–133
then by others.2,4,5 LCH is known to be associated with other neoplasms, such as lymphoma, leukaemia or lung cancer,6 but the association with PTC remains rare and unclear, as there have only been a few reported cases. However, a recent study5 showed an increased presence of CD1a-positive dendritic cells in PTC. In conclusion, LCH thyroid involvement is rare, but the diagnosis is possible based on a representative highly cellular cytology sample, close examination and correlation with clinical data. Surgical removal seems to be the gold standard treatment for isolated LCH, whereas disseminated disease requires systemic therapy. Associated PTC may require further treatment, such as iodine therapy, but there are no standard recommendations. M. Bucau*, H. Dahan†, V. Meignin‡, M.-E. Toubert§, A. Tazi¶ and B. Cochand-Priollet* *Department of Pathology, †Radiology, Lariboisiere Hospital, ‡Department of Pathology, §Nuclear Medicine and ¶Respiratory Department, Reference Center for Langerhans Cell Histiocytosis, INSERM UMR 717, St. Louis Hospital-University Paris Diderot, Paris, France References 1. Patten DK, Wani Z, Tolley N. Solitary Langerhans histiocytosis of the thyroid gland: a case report and literature review. Head Neck Pathol 2011;6:279–89. 2. Wohlschlaeger J, Ebert S, Sheu S-Y, Schmid KW, T€ otsch M. Immunocytochemical investigation of Langerin (CD207) is a valuable adjunct in the cytological diagnosis of Langerhans cell histiocytosis of the thyroid. Pathol Res Pract 2009;205:433–6. 3. Goldstein N, Layfield LJ. Thyromegaly secondary to simultaneous papillary carcinoma and histiocytosis X. Report of a case and review of the literature. Acta Cytol 1991;35:422–6.
131
132
Correspondence
4. Pusztaszeri MP, Sauder KJ, Cibas ES, Faquin WC. Fineneedle aspiration of primary Langerhans cell histiocytosis of the thyroid gland, a potential mimic of papillary thyroid carcinoma. Acta Cytol 2013;57:406–12. 5. Pusztaszeri MP, Sadow PM, Faquin WC. Association of CD1a-positive dendritic cells with papillary thyroid carcinoma in thyroid fine-needle aspirations. Cancer Cytopathol 2013;121:206–13. 6. Egeler RM, Neglia JP, Aric M o et al. The relation of Langerhans cell histiocytosis to acute leukemia, lymphomas, and other solid tumors. The LCH-Malignancy Study Group of the Histiocyte Society. Hematol Oncol Clin North Am 1998;12:369–78.
Report of a case emphasizing the clinical utility of fine needle aspiration cytology in the diagnosis of histoid leprosy DOI:10.1111/cyt.12144
Dear Editor, There has been a significant literature on the role of fine needle aspiration cytology (FNAC) in the diagnosis of leprotic lesions, such as pure neuritic, reactionary and rare cases of skeletal leprosy.1,2 Histoid leprosy is a distinct and rare variant of leprosy manifesting with characteristic skin lesions, histopathological features and bacterial morphology.3 Owing to the lack of obvious lymphocytic response, pathologically, it often mimics spindle cell tumours. The literature on the cytodiagnosis of histoid leprosy is rather sparse. Nonetheless, because of its characteristic cytomorphological presentation, it is easily diagnosable by FNAC.4 We report a case highlighting the clinical utility of FNAC in its diagnosis. A 55-year-old man presented with multiple asymptomatic papular and nodular lesions over the trunk and face of 2 years’ duration. Peripheral nerves were thickened. Slit-skin smear examination and biopsy of one of the cutaneous nodules confirmed the diagnosis of lepromatous leprosy with a bacteriological index of 6+. The patient was started on multidrug therapy for multibacillary leprosy. During the course of 5 months of therapy, he developed fresh, firm, 0.8 9 0.8-cm2 to 1.5 9 1.5-cm2 nodular lesions on the right hand (Figure 1a,b), Correspondence: N. Siddaraju, Professor of Pathology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry 605 006, India Tel.: +91-99-44426595; Fax: +91-0413-2272067; E-mail: [email protected]
which were suspected to be caused by erythema nodosum leprosum (ENL). The nodules were subjected to FNAC by the standard procedure. Air-dried and 95% ethanol-fixed smears were stained with routine May–Gr€ unwald–Giemsa (MGG) and Papanicolaou (Pap) stains. Fites stain was performed on one of the air-dried smears. The smears were highly cellular with tight clusters and fragments of spindle cells, in places arranged in a vague palisading manner and having foamy cytoplasm with distinct negative images. Fine vacuolation and negative images were also appreciated in the smear background of MGG smears (Figure 2a–c). No intervening stroma or obvious neutrophilic/lymphocytic infiltrate was seen within the spindle cell fragments, and the Fites stain was strongly positive, corresponding to the negative images (Figure 2d). A cytological diagnosis of ‘histoid leprosy’ was rendered. The term ‘histoid leprosy’ was originally coined in 1963 by Wade.5 Most commonly, it affects multibacillary patients who are on irregular and inadequate dapsone therapy; however, it can also arise de novo.3 This distinct entity received adequate attention only after Sehgal et al.6 documented its immunological profile in 1985. Histoid leprosy is said to be the result of an altered growth pattern of Mycobacterium leprae, caused by the loss of immunity in a localized area. Nodules of histoid leprosy are often confused with lepromatous nodules, and cytomorphology can play a substantial role in distinguishing between the two.4 There are only rare studies and reports describing the cytomorphological features of histoid leprosy.3,4 Two patterns of cytological presentation have been described.4 The most common presentation is a high cell yield3,4 with multilayer palisades of spindle-shaped histiocytes on an endothelial vascular core.4 The spindly macrophages show a dense
(a)
(b)
Figure 1. Clinical photographs showing nodules on the right wrist (a) and hand (b). © 2014 John Wiley & Sons Ltd Cytopathology 2014, 26, 126–133
Copyright of Cytopathology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
