Crystal-storing histiocytosis associated with lymphoplasmacytic lymphoma mimicking Weber-Christian disease: immunohistochemical, ultrastructural, and gene-rearrangement studies

A novel approach to diagnosing crystal-storing histiocytosis: utility of scanning electron microscopy for formalin-fixed paraffin-embedded tissue specimens

Crystal-storing histiocytosis (CSH) is a rare disorder that shows infiltration of histiocytes with an aberrant cytoplasmic accumulation of crystalline structures and is often accompanied by lymphoproliferative-plasma cell disorders (LP-PCD) as background diseases. The diagnosis of CSH requires identification of crystalline structures that accumulate in the infiltrating histiocytes, which may be challenging by optical microscopy alone. In this case report, we describe an atypical course of systemic CSH with multifocal fibrosclerosis of an unknown background disease that was diagnosed by ultrastructural observation, including transmission electron microscopy (TEM) and scanning electron microscopy (SEM), in pathological autopsy. In addition, crystalline structures were successfully identified by scanning electron microscopic observations using formalin-fixed and paraffin-embedded (FFPE) tissue from biopsy specimens taken before death. Since CSH was identified by SEM in a tiny biopsy specimen, observation of histiocytic infiltrative lesions by SEM using FFPE tissue may lead to early detection of and initiation of treatment for CSH.

Crystal-Storing Histiocytosis: The Iceberg of More Serious Conditions

Crystal-storing histiocytosis is a rare condition that is histologically characterized by intracellular cytoplasmic crystalline inclusions. It usually presents monoclonal immunoglobulins that deposit within histiocytes, which accumulate and affect different organs of the human body and are commonly associated with lymphoproliferative conditions, especially those with plasmacytic differentiation. The prognosis of this condition is variable and related to the underlying clinical disease. In this review article, we aim to describe and discuss the clinical and pathological characteristics of crystal-storing histiocytosis based on the available literature and to provide a thorough differential diagnosis.

Localized ocular crystal-storing histiocytosis and associated lymphoma - Report of two cases and review of literature

Purpose

Observations

Conclusion and Importance

Immunoglobulin-Storing Histiocytosis: A Case Based Systemic Review

Crystal-storing histiocytosis (CSH) is a rare event in disorders associated with monoclonal gammopathy and is mostly associated with the accumulation of immunoglobulins (Igs) in the cytoplasm of histiocytes. In this article, we present a case of a 75-year-old female with IgG kappa monoclonal gammopathy of undetermined significance (MGUS) and signs of a non-crystallized version of immunoglobulin-storing histiocytosis (IgSH) in a vertebra corpus. Furthermore, we performed a literature review based on all cases of storing histiocytosis identified by literature search between 1987 and 2020 and identified 140 cases in total. The median age at diagnosis was 60 years (range 18–91), with an equal sex distribution (51% men). The majority of the patients had an underlying neoplastic B-cell disorder, most often multiple myeloma (MM), MGUS, or lymphoplasmacytic lymphoma (LPL). The main affected organ systems or tissue sites were bone (n = 52), followed by head and neck (n = 31), kidney (n = 23), lung (n = 20), and gastrointestinal (GI)-tract (n = 18). IgG was the main immunoglobulin class involved, and most cases were associated with kappa light chain expression. We conclude that IgSH is a rare disease entity but should be considered with unusual findings in several organ systems associated with monoclonal gammopathy, especially with kappa light chain expression.

Massive Bone Marrow Crystal-Storing Histiocytosis in a Patient with Iga-Lambda Multiple Myeloma and Extensive Extramedullary Disease. A Case Report

We report a case of multiple myeloma (MM) displaying an unusual course, with metastatic spread in uncommon sites (gastroduodenal and upper respiratory tract, breast, skin and liver) and with a fatal outcome. In our patient this plasma cell neoplasm was associated with a rare condition named crystal-storing histiocytosis (CSH), resulting from the storage in reactive histiocytes of crystalline immunoglobulin inclusions. These crystal-forming paraprotein components are secreted by the neoplastic plasma cells and give rise to the crystalline material of the histiocytes only after their ingestion and degradation by the same histiocytes. In this disorder crystal-storing cells may be present in various tissues (in our case mainly in bone marrow), often with functional alterations of the involved organs. In our opinion the association of this “atypical” MM with CSH is to be considered an uncommon event.

Non-neoplastic histiocytic and dendritic cell disorders in lymph nodes

Benign and malignant proliferations of histiocytes and dendritic cells may be encountered in lymph nodes. Reactive histiocytic and dendritic cell infiltrates occur in response to diverse stimuli and in addition to causing lymphadenopathy, may be present unexpectedly in lymph nodes excised for other indications. This review summarizes the pathogenesis and histopathological features of the various non-neoplastic histiocytic and dendritic cell infiltrates that can occur in lymph nodes.

Paraprotein deposits in the skin

Cutaneous manifestations secondary to paraprotein deposits in the skin include a group of different disorders that although rare, may be the first clinical manifestation of the underlying hematologic dyscrasia. In this article we review the clinical manifestations and histopathologic findings of the processes that result from specific deposition of the paraprotein in different structures of the skin. Paraneoplastic processes frequently associated with hematologic malignancies will not be covered in this review. Some of the disorders included here result from deposition of the intact paraprotein in the skin, whereas in other cases the lesions are due to deposition of modified paraproteins in the form of amyloid substance, cryoglobulins, or crystalglobulins. Cutaneous amyloidoma refers to nodular dermal deposits of amyloid derived from immunoglobulin light chains produced by local plasma cells in the absence of systemic amyloidosis. Dermatologists and dermatopathologists should be aware of the clinical and histopathologic features of these rare disorders because sometimes the cutaneous lesions are the first sign of an underlying silent hematologic malignancy with paraproteinemia.

Low-Grade Lymphomas in the Background of Numerous Multinucleated Histiocytic Giant Cells Can Be Missed

Epithelioid granulomas, epithelioid histiocytes, and occasional multinucleated giant cells are recognizable pathologic findings in lymphomas, particularly in Hodgkin lymphomas. The giant cells could be neoplastic and nonneoplastic. The nonneoplastic giant cells are of different histogenesis. They include, in the majority of cases, histiocytes. Usually, they are minor easily recognizable components of the nodal lymphomas. To our knowledge, low-grade B-cell non-Hodgkin lymphomas with numerous multinucleated histiocytic giant cells without epithelioid granulomas or crystals formation have not been previously reported. This might present a diagnostic challenge for the unwary pathologists since the diagnostic workout will be focused on the giant cells that might mask the apparently mixed bland-looking neoplastic lymphocytic background. We report a case of a 24-year-old woman who presented with generalized lymphadenopathy, organomegaly, and B-symptoms. The lymph nodes were enlarged and diffusely effaced with a striking feature of numerous multinucleated giant cells with a background of apparently mixed population of small lymphocytes and plasma cells. Initially, the diagnosis of a small low-grade lymphoma was histologically missed and the focus was on the differential diagnoses of the giant cells. Immunohistochemistry and flow cytometry raised the suspicion of masked small lymphocytic lymphoma that was subsequently confirmed by molecular studies. The rarity of small lymphocytic lymphoma and the unusual histologic features in this case confounded the clinical and pathologic diagnosis.

Crystal-storing histiocytosis: a clinicopathological study of 13 cases

AIMS

Crystal-storing histiocytosis (CSH) is a rare lesion composed of histiocytes with abnormal intralysosomal accumulation of immunoglobulin (Ig) as crystals, reported in patients with plasmacytic/lymphoplasmacytic neoplasms. The aims of this study were to report the clinicopathological features of 13 patients with CSH, and to describe the proteomic composition of the crystals in three cases analysed by mass spectrometry (MS).

METHODS AND RESULTS

There were seven men and six women, with a median age of 60 years (range, 33-79 years). CSH was generalized in one patient (8%) and localized in 12 (92%) patients, involving various sites. CSH was associated with a low-grade B-cell lymphoma with plasmacytoid differentiation or a plasma cell neoplasm in all cases. In 10 (77%) cases, CSH represented >50% of the neoplastic infiltrate. According to immunohistochemical studies, histiocytes were positive for monotypic kappa in 5 (50%) cases, and for monotypic lambda in 4 (40%) cases; in 1 (10%) case, the results were equivocal. MS analysis of the histiocyte contents in all three tested cases showed a predominance of variable-region fragments of Ig light and/or heavy chains.

CONCLUSIONS

CSH is frequently associated with an underlying lymphoplasmacytic neoplasm. MS findings suggest that Ig alterations and/or possibly defects in the ability of histiocytes to process Ig play a role in pathogenesis.

Pseudo-Peritoneal Carcinomatosis Presentation of a Crystal-Storing Histiocytosis With an Unmutated Monoclonal κ Light Chain

Crystal-storing histiocytosis (CSH) is a rare complication of monoclonal gammopathies caused by accumulation of crystalline material inside macrophages, and it may result in a variety of clinical manifestations depending on the involved organs. Although immunoglobulin κ light chains (LCs) seem to be the most frequent pathogenic component, very few molecular data are currently available.A 69-year-old man presented with a very poor performance status. Remarkable features were mesenteric lymph node enlargement and proteinuria, including a monoclonal κ LC. Light and electron microscopy studies revealed the presence of crystals within macrophages in the lymph nodes, bone marrow, and kidney, leading to the diagnosis of CSH. The pathogenic κ LC variable domain sequence was identical to the germline Vk3-2001/Jk201 gene segments, without any somatic mutation, suggesting an extra-follicular B cell proliferation.The patient was successfully treated with 4 cycles of bortezomib and dexamethasone. After a 12-month follow-up, he remains in hematological and renal remission.CSH may present as pseudo-peritoneal carcinomatosis and relate to a monoclonal κ LC encoded by an unmutated gene. Bortezomib-based therapy proved efficacious in this case.

Panniculitis with crystals induced by etanercept subcutaneous injection

Panniculitis with lipid crystallization within adipocytes may be seen in several disorders, including crystal-storing histiocytosis, gouty panniculitis, subcutaneous fat necrosis of the newborn, post-steroid panniculitis, sclerema neonatorum, oxalosis and subcutaneous fungal infections by mucormycosis, zygomycosis or aspergillosis. Panniculitis at the sites of subcutaneous injection of drugs are frequent, but to our knowledge no crystals have been described in the drug-induced panniculitis at the sites of subcutaneous injections. We report on a patient who developed a panniculitis with lipid crystallization at the site of etanercept injection.

Cutaneous crystal storing histiocytosis: a report of two cases

Crystal storing histiocytosis (CSH) is a rare condition where crystals accumulate in the cytoplasm of macrophages and is usually associated with a lymphoplasmacytic neoplasm producing a monoclonal immunoglobulin with kappa light chain. CSH with primary manifestation in the skin is extraordinarily rare and limited to four case reports in the literature. Here we present two cases of cutaneous CSH. One case is that of an 80 year old woman who presented with bilateral periorbital oedema with yellow discolouration. Skin biopsy showed dermal CSH in association with a neoplastic lymphoplasmacytoid infiltrate showing IgM kappa light chain restriction. Subsequent work up led to the discovery of Waldenstrom's macroglobulinemia. She had an indolent clinical course but died 6 years later from transformation into a diffuse large B cell lymphoma in the bone marrow. The other case is that of a 52 year old man who was recently diagnosed with multiple myeloma and developed a pruritic rash on his back during chemotherapy. Skin biopsy showed Grover disease (transient acantholytic dermatosis) and crystal storing macrophages in the superficial dermis. He died 4 years later after a protracted clinical course involving multiple cycles of chemotherapy and numerous complications. In both patients cutaneous CSH occurred early in the course of their lymphoplasmacytic malignancy and its development did not herald rapid clinical decline.

Crystal-storing histiocytosis: report of a case, review of the literature (80 cases) and a proposed classification

We report a case of crystal storing histiocytosis (CSH) of the upper lip and cheek in a 51-year-old woman and review the clinicopathologic features of 80 cases in the literature. These occurred in 41 men and 39 women with a respective mean age of 59 and 61 years (range 17-81 years). Forty-six patients (58%) had localized CSH, and, of these, 16 (35%) occurred in the head and neck, with the most common site being the eye/orbit. The remaining 34 patients (42%) had generalized CSH primarily involving bone marrow, liver, lymph nodes, spleen and/or kidney. Regardless of whether the CSH was localized or generalized, the vast majority of patients (90%) had an underlying lymphoproliferative or plasma cell disorder, especially multiple myeloma, lymphoplasmacytic lymphoma, or monoclonal gammopathy of undetermined significance. In 7 cases (8.8%), the CSH was associated with a variety of benign disorders, often with an inflammatory background, and no evidence of a clonal lymphoproliferative or plasma cell disorder. Treatment and prognosis varied according to the underlying disease. A classification of CSH based on etiology and/or associated disease and chemical composition of the crystal is proposed, rare non-immunoglobulin variants of CSH are discussed, and a differential diagnosis of other potentially confusing lesions is provided.

Pulmonary crystal-storing histiocytosis diagnosed by computed tomography-guided fine-needle aspiration

Crystal-storing histiocytosis (CSH) is a rare process most often occurring in conjunction with an underlying hematopoietic neoplasm, usually multiple myeloma or low-grade B-cell lymphoma. We report the first case of pulmonary CSH diagnosed by fine-needle aspiration biopsy. A patient with a history of urothelial carcinoma developed a lung nodule, which was evaluated by fine-needle aspiration biopsy. Cytologic examination revealed macrophages with abundant cytoplasmic crystals diagnostic of CSH. Based on this cytologic interpretation, additional clinical laboratory evaluation was pursued and revealed a previously unknown monoclonal serum protein. CSH must be differentiated from other non-neoplastic and neoplastic lesions and when diagnosed, should trigger a search for an underlying lymphoproliferative disorder.

Crystal-storing histiocytosis as a cause of symptomatic cardiac mass

Crystal-storing histiocytosis is a rare disorder that is typically associated with low-grade B-cell lymphomas and monoclonal gammopathy. We present a 64-year-old man with a prior history of weakness and weight loss and hematologic evaluation that had revealed immunoglobulin G kappa monoclonal light chains in the serum and negative bone marrow biopsy. He presented with supraventricular tachyarrhythmia and a right atrial mass seen on echocardiogram and excised surgically. Histologically, the tumor was composed of sheets of macrophages infiltrating the atrial myocardium. The histiocytes were filled with multiple needle-shaped, periodic acid-Schiff-negative crystals. These cells and associated plasma cells failed to show clonal light chain restriction by in situ hybridization or immunohistochemistry, and there was no area of lymphoma in the tumor. Ultrastructural examination showed numerous stick-like, trapezoidal, or polygonal dense crystals in the cytoplasm of histiocytes corroborating the diagnosis of crystal-storing histiocytosis. Although rare, crystal-storing histiocytosis should be included in the differential diagnosis of heart masses in patients with hematologic conditions associated with monoclonal gammopathy.

Deposition-associated diseases related with a monoclonal compound

Up to 3% of adults over 50 years of age show a monoclonal peak values in blood or urine. Findings and prognosis will be distinct in view of the nature of this factor. In B-cell neoplasias (multiple myeloma, Waldeström macroglobulinaemia, chronic myeloid leukaemia and non-Hodgkin lymphoma) the clinical pattern is dominated by the systemic effects produced by the expansion of the malign clone; the monoclonal protein may result in hyperviscosity syndrome or renal damage. On the other hand, there are other less frequent processes called diseases associated to monoclonal components, where the main clinical manifestations and prognosis depend of the biological effects of the monoclonal protein. With reference to this last group, which is the objective of this revision, no bone lesions, anaemia or a greater tendency to infections usually occur when compared with the first group. Even so, there are some cases of interposition between both groups: for instance, type IgM immunoglobulin present in Waldeström macroglobulinaemia may have cold agglutinin activity, and in the case of multiple myeloma, the clone may secrete amyloidogenic light chains.

Crystal-storing Histiocytosis due to Massive Accumulation of Charcot-Leyden Crystals: A Unique Association Producing Colonic Polyposis in a 78-year-old Woman With Eosinophilic Colitis

Crystal-storing histiocytosis is a rare diagnosis that to date has only been associated with 2 conditions: intracytoplasmic accumulation of crystallized immunoglobulins in patients with lymphoproliferative disorders or plasma cell dyscrasias, and histiocytic accumulations of phagocytosed clofazimine, a drug used to treat lepromatous leprosy. We describe a 78-year-old woman with a past medical history of dermatologic mastocytosis and peripheral eosinophilia who presented with diarrhea and weight loss, and was found at colonoscopy to have polyposis limited to the right and transverse colon. She eventually underwent subtotal colectomy to remove the segment of polyposis. At gross examination, the colonic mucosa contained numerous polyps ranging from 1 to 7 mm which on histologic evaluation proved to represent mucosal and submucosal collections of histiocytes whose cytoplasm was distended by numerous brightly eosinophilic crystals. An intense eosinophilic infiltrate surrounded the histiocyte collections and also mildly involved the intervening colonic mucosa and superficial submucosa. Electron microscopy confirmed the presence of intracytoplasmic material identical to Charcot-Leyden crystals within histiocytes, representing the breakdown products of degranulated eosinophils. This is the first reported case of crystal-storing histiocytosis produced by massive accumulation of Charcot-Leyden crystals in eosinophilic colitis.

Crystal storing histiocytosis of the skin associated with multiple myeloma

BACKGROUND

Crystal storing histiocytosis (CSH) imitating rhabdomyoma is a very rare disease entity involving different tissues. The skin is involved in extremely rare cases.

OBJECTIVES

To describe the clinical and histopathological characteristics in a patient with unusually extensive skin involvement.

OBSERVATIONS

A 62-year-old woman presented with a large red infiltrated verrucosus lesion on the anterior aspect of the chest and on the neck. The skin biopsy revealed histiocytes throughout the whole dermis containing thin crystalloid structures in the cytoplasm. Upon histopathological examination, crystal-storing histiocytosis was diagnosed and consequently a hematological examination revealed multiple myeloma IgG Kappa. Skin involvement by CSH proceeded the diagnosis of multiple myeloma by 4 years.

CONCLUSIONS

Phagocytosis of crystals of immunoglobulins by histiocytes (crystals storing histiocytosis) is a rare symptom associated most often with lymphoproliferative disease. The clinical picture is not characteristic, in the histopathologic picture it is striking similarity to rhabdomyoma. The skin involvement by crystal storing histiocytosis can be the first symptom of malignant lymphoma that can proceed the hematological malignancy by years.

Crystal-storing histiocytosis associated with MALT lymphoma of the ocular adnexa: a case report with review of literature

We report a case of crystal-storing histiocytosis (CSH) associated with mucosa-associated lymphoid tissue (MALT) lymphoma of the ocular adnexa. The patient was an 81-year-old woman who presented with a 5-month history of a slowly enlarging tumor on her left lower eyelid. The tumor was 2 cm in the largest diameter, involving both inferior oblique and inferior rectus muscles. Histological examination revealed that the tumor was composed predominantly of sheets of spindle-shaped cells resembling striated muscle cells, and scattered aggregates of atypical lymphoid cells at the periphery of the tumor, showing prominent plasmacytoid differentiation. Immunohistochemical and ultrastructural analyses demonstrated that the spindle-shaped cells were CD68-positive histiocytes containing abundant rod-like and/or rectangular crystals in their cytoplasm, consistent with the diagnosis of CSH. The scattered aggregates of atypical lymphoid cells were diagnosed as MALT lymphoma based upon their immunophenotype, featuring diffusely positive staining for CD20, but negative for CD3, CD5, and CD10, and monotypic expression of IgM-kappa in cells with plasmacytoid differentiation. Although CSH is a well-recognized manifestation in lymphoproliferative disorders in the literature, CSH complicated by MALT lymphoma has only very rarely been reported. Given the rarity of this, difficulties in diagnosis may arise especially in cases where histiocytic proliferation overwhelms the underlying lymphoproliferative diseases.

Pulmonary extranodal marginal zone lymphoma with massive crystal storing histiocytosis

We present an incidentally discovered, unusual case of pulmonary bronchial mucosa-associated lymphoid tissue lymphoma associated with massive crystal storing histiocytosis in a 69-year-old woman. The neoplastic process was masked by large numbers of epithelioid and spindled histiocytes containing crystalline material. Histochemical stains showed intracytoplasmic crystals and immunoperoxidase staining confirmed the histiocytic nature of the swollen cells. Electron microscopy demonstrated the characteristic appearance of immunoglobulin crystals. Lymphoepithelial lesions were identified on immunohistochemical staining, compounding suspicions of an underlying lymphoid neoplasm. Molecular studies later revealed a monoclonal B-cell population. The patient had no systemic evidence of a paraproteinemia. Crystal storing histiocytosis is a rare phenomenon in which macrophages accumulate light chain or immunoglobulin crystalline inclusions. The disease may be systemic, or localized as in this case. It is usually associated with the excess production of a monoclonal immunoglobulin, although there have been many case reports without this feature. An overview of crystal storing histiocytosis is given.

Crystal Deposition in a Case of Cutaneous Rosai-Dorfman Disease

Rosai-Dorfman Disease (RDD) is an idiopathic reactive proliferation of distinctive histiocytes that have abundant cytoplasm and commonly exhibit intracytoplasmic ingestion of inflammatory cells (emperipolesis). The histiocytes are immunopositive for S100 protein and are typically associated with an infiltrate of lymphocytes, plasma cells, and neutrophils. The classic clinical presentation is massive enlargement of (usually) cervical lymph nodes with a histologic appearance that mimics exaggerated sinus histiocytosis. RDD can also involve extra-nodal sites and skin involvement is common either as part of disseminated disease or as a result of primary disease. We report an exceptional case of cutaneous RDD with crystal deposition in a young male presenting with skin nodules. Skin biopsy showed classic features of cutaneous RDD with the additional feature of conspicuous rhomboidal and needle-shaped crystals within the cytoplasm of many lesional plasma cells, histiocytes, and also in an extra-cellular location. The plasma cells were polyclonal by light chain immunostaining. Crystal deposition has not been reported to date in RDD and is likely a result of the reactive plasma cell proliferation.

Pulmonary crystal-storing histiocytosis and extranodal marginal zone B-cell lymphoma associated with a fibroleiomyomatous hamartoma

Crystal-storing histiocytosis (CSH) is a rare disorder occurring in patients with lymphoproliferative diseases, predominantly in cases of multiple myeloma and low-grade B-cell lymphoma. To the best of our knowledge, only three cases of pulmonary CSH have been reported in the English literature and one of them was associated with a low-grade B-cell lymphoma (immunocytoma). We document a case of a 59-year-old man with bilateral lung masses in which a right middle lobe pulmonary lobectomy specimen showed CSH associated with an extranodal marginal-zone B-cell lymphoma. A single nodule showing features of fibroleiomyomatous hamartoma was present in a wedge biopsy specimen from the left lung. Two nodules within the right middle lobe were composed of sheets of histiocytic cells with abundant eosinophilic cytoplasm resembling striated muscle cells. In addition, there were nodular aggregates and a more diffuse infiltrate of small slightly atypical centrocyte-like lymphocytes, as well as bronchial lymphoepithelial lesions. Immunohistochemistry performed on paraffin-embedded sections demonstrated that the histiocytic cells were immunoreactive with the KP-1 (CD68) antibody while the lymphocytic infiltrate was CD20 positive, co-expressed for CD43, and was negative for CD3, CD5, and CD10. Genotypic analysis demonstrated the presence of an immunoglobulin heavy-chain gene rearrangement, indicating the presence of a monoclonal B-cell population. These features were consistent with pulmonary CSH associated with extranodal marginal-zone lymphoma of baltoma type.

Intracytoplasmic immunoglobulin crystals in follicular lymphoma

We report a case of follicular lymphoma with crystal inclusions. Swollen lymph nodes taken from the left neck of a 53- year-old Japanese woman were replaced by follicular proliferation of atypical centroblastic and centrocytic cells with intracytoplasmic crystal inclusions. The crystals were confined to lymphoma cells and were not found in histiocytes. Lymphoma cells were positively immunostained with lambda light chain and mu heavy chain, but the crystals were only weakly so. In situ hybridization of light chains disclosed a monoclonal expression of lambda light chain mRNA in lymphoma cells. The crystals had a periodic linear substructure with about 5-nm intervals. The worldwide literature reports 8 cases, including the current case of non-Hodgkin's lymphoma with crystals confined to the neoplastic cells. The cases did not accompany paraproteinemia and crystal-storing histiocytosis and appear to follow a favorable clinical outcome.

Generalized crystal-storing histiocytosis associated with monoclonal gammopathy: molecular analysis of a disorder with rapid clinical course and review of the literature

Crystal-storing histiocytosis (CSH) is a rare event in disorders associated with monoclonal gammopathy. The intracellular crystal formation is almost always accompanied by the expression of κ light chains. However, the exact mechanism for the storage has not been clarified until now. We report a case of generalized CSH in a 73-year-old man who presented with IgA κ paraproteinemia and paraproteinuria. The initially observed CSH in the bone marrow biopsy was associated with the clinical and pathomorphologic features of a monoclonal gammopathy of undetermined significance. The progression of disease could not be affected by steroid therapy and the patient died of septic shock 7 months after detection of CSH. At the time of autopsy there was evidence for multiple myeloma and generalized CSH. Two-dimensional gel electrophoresis of liver tissue combined with immunoblotting revealed the massive storage of heavy chains of α type and light chains of κ type, each in a monoclonal pattern. Analysis of the stored κ light chain by nanoelectrospray-ionization mass spectrometry indicated that it belongs to the variable κI variability subgroup. We identified some unusual amino acid substitutions including Leu59, usually important for hydrophobic interactions within a protein, at a position where it has never been previously described in plasma cell disorders. In conclusion, we present the first case of CSH with molecular identification of the stored κ subgroup and detection of unusual amino acid substitutions. Our results suggest that conformational alterations induced by amino acid exchanges represent a crucial pathogenic factor in CSH.

Extranodal marginal zone B-cell lymphoma of the lacrimal gland associated with crystal-storing histiocytosis

OBJECTIVE

Crystal-storing histiocytosis (CSH) is a very rare immunoglobulin (Ig) deposition disorder that can be associated with B-cell neoplasms as well as some reactive Ig-secreting lymphoproliferative disorders. This article reports the clinical, histopathologic, and molecular biologic findings of CSH in association with an extranodal marginal zone lymphoma (EMZL) of the lacrimal gland.

DESIGN

Interventional case report with clinicopathologic correlation.

INTERVENTION

Treatment consisted of conjunctival and orbital biopsies, as well as low-dose radiation of the left orbit.

METHODS

Histopathologic findings of the conjunctival and orbital biopsies were compared. Further, extensive immunohistochemistry, polymerase chain reaction (PCR) for the detection of Ig heavy chain (IgH) gene rearrangement, Gene Scan analysis, and DNA sequencing were performed on all tissues.

RESULTS

The tumor manifestations in the specimens demonstrated a similar morphologic and immunophenotypic characteristics consistent with the diagnosis of EMZL. Immunoglobulin H PCR and Gene Scan analysis showed B cells derived from the same clone. In association with the orbital EMZL were large accumulations histiocytes filled with refractile crystals, consistent with the diagnosis of CSH.

CONCLUSIONS

The current case describes an EMZL of the lacrimal gland appearing 5 years after excision and low-dose radiation of a conjunctival lymphoma. The orbital recurrence was associated with surrounding CSH, a rare Ig storage disorder more often reported in patients with multiple myeloma or lymphoplasmacytic lymphoma or immunocytoma. Ophthalmic pathologists should be aware of the diagnosis when reviewing orbital biopsies, because difficulties may arise when the crystal-storing macrophages occupy more tissue space than the Ig-secreting cells or when they resemble cell types such as rhabdomyoblasts.

Panniculitis. Part II. Mostly lobular panniculitis

The second part of our review of panniculitis summarizes the clinicopathologic features of the mostly lobular panniculitides. Erythema induratum of Bazin (nodular vasculitis) represents the most common variant of lobular panniculitis with vasculitis, although controversy persists about the nature of the involved vessels. Mostly lobular panniculitides without vasculitis comprise a series of disparate disorders. These include sclerosing panniculitis that results from chronic venous insufficiency of the lower extremities; panniculitis with calcification of the vessel walls such as calciphylaxis and oxalosis; and inflammatory diseases with crystals within the adipocytes such as sclerema neonatorum, subcutaneous fat necrosis of the newborn, and poststeroid panniculitis. Connective tissue diseases, such as systemic lupus erythematosus and dermatomyositis, pancreatic diseases, and alpha(1)-antitrypsin deficiency may also show a mostly lobular panniculitis with characteristic histopathologic features. Lobular panniculitis may also be an expression of infections, trauma, or factitial causes involving the subcutaneous fat. Lipoatrophy refers to a loss of subcutaneous fat due to a previous inflammatory process involving the subcutis, and it may be the late-stage lesion of several types of panniculitis. In contrast, lipodystrophy means an absence of subcutaneous fat with no evidence of inflammation and often the process is associated with endocrinologic, metabolic, or autoimmune diseases. Finally, cytophagic histiocytic panniculitis is the term that has been used to describe two different processes: one is inflammatory, a lobular panniculitis, and the other one is neoplastic, a subcutaneous T-cell lymphoma. The only common feature of these two different processes is the presence of cytophagocytosis in the lesions. (J Am Acad Dermatol 2001;45:325-61.)

LEARNING OBJECTIVE

At the completion of this learning activity, participants should be familiar with the pathogenesis, clinical manifestations, histopathologic findings, and treatment options for the most frequent variants of the lobular panniculitides.

Transformation of monocytoid B-cell lymphoma to large cell lymphoma associated with crystal-storing histiocytes

We report a case of crystal-storing histiocytosis associated with large cell lymphoma in a patient with a history of monocytoid B-cell lymphoma 10 years previously. The cervical lymph node biopsy showed a diffuse proliferation of large lymphocytes with vesicular nuclear chromatin and distinct nucleoli. These lymphocytes were associated with numerous immunoglobulin lambda light-chain crystal-storing histiocytes, which morphologically resembled rhabdomyoblasts. Occasional lymphoid cells also showed large immunoglobulin crystals. This case establishes the association of crystal-storing histiocytes with lymphomas of mucosa-associated lymphoid tissue and emphasizes the need for immunophenotyping to distinguish these unusual cases from other tumors, particularly adult rhabdomyomas.

Clofazimine-induced crystal-storing histiocytosis producing chronic abdominal pain in a leprosy patient

Clofazimine-induced crystal-storing histiocytosis is a rare but well-recognized condition in the literature. Besides the common reddish discoloration of the skin, clofazimine produces gastrointestinal disturbances-sometimes severe abdominal pain, prompting exploratory laparotomy, because pathologic and radiologic findings can produce diagnostic difficulties if the pathologic changes caused by clofazimine are not recognized. The authors report such a case in a leprosy patient to emphasize the importance of history taking, the radiologic abnormalities of the small intestine, and the pathologic findings in small intestine and lymph node biopsies. Clofazimine crystals are red in the frozen section and exhibit bright-red birefringence. However, they are clear in routinely processed histologic sections because they dissolve in alcohol and organic solvents. They also appear as clear crystal spaces during electron microscopic study, but some osmiophilic bodies can be observed. Histiocytosis caused by clofazimine crystals produces infiltrative lesions in radiologic studies mimicking malignant lymphoma or other infiltrative disorders. Associated plasmacytosis in the histologic sections can simulate lymphoplasmacytic lymphoma or multiple myeloma with crystal-storing histiocytosis. With the knowledge of this rare condition caused by clofazimine, appropriate management to avoid an unnecessary laparotomy is possible.

Electron microscopy in tumor diagnosis: indications for its use in the immunohistochemical era

The electron microscope reveals much more information on tumor cell structure than can be obtained with the light microscope, and some of the data are useful in diagnostic studies. In this review, major contributions of electron microscopy in the main tumor categories are discussed. To select between immunocytochemistry and electron microscopy, the probable contributions of each in the context of the particular case must be assessed. Usually, electron microscopy will only be requested after a battery of immunostaining procedures has been performed and found to be insufficient, but there are occasions when ulstrastructural study is logically the first choice after routine light microscopy. It is worth taking tissue for possible electron microscopy from any tumor that is known or anticipated to be a diagnostic problem.

Crystal-storing histiocytosis and immunocytoma associated with multifocal fibrosclerosis

AIMS

Crystal-storing histiocytosis is a rare disorder described in patients with lymphoproliferative diseases, mainly in cases of multiple myeloma but also in lymphoplasmacytic lymphoma (immunocytoma). Most cases involve one single organ which, in the majority, is related directly to the presence of tumour. We describe a 44-year-old man with a clinical picture of multifocal fibrosclerosis (with mesenteric panniculitis, peritoneal, mediastinal and orbital fibrosis) in which the autopsy showed a systemic infiltrate of crystal-storing histiocytes and functional alteration of the organs involved, associated with IgG-kappa type immunocytoma.

METHODS AND RESULTS

Histology showed a systemic infiltration, with a predilection for adipose tissue, by a diffuse cellular infiltrate composed of small lymphocytes, plasmacytoid lymphocytes and plasma cells, admixed with large number of crystal-storing histiocytes. Intracytoplasmic crystals were not identified either in the plasma cells or plasmacytoid lymphocytes. The neoplastic cells and the crystalline inclusions displayed reactivity with antibodies for IgG and the kappa light chain. A polymerase chain reaction study for the IgH gene showed a monoclonal rearrangement. Ultrastructural studies showed needle-shaped crystals surrounded by a single unit membrane.

CONCLUSION

This case is, to the authors' knowledge, the first to be described in which crystal-storing histiocytosis is associated with a clinical picture of multifocal fibrosclerosis, which suggests that lymphoproliferative processes should be considered in the differential diagnosis of the various conditions associated with multifocal fibrosclerosis.

Pulmonary immunocytoma with massive crystal storing histiocytosis: a case report with review of literature

An unusual immunocytoma (lymphoplasmacytoid lymphoma) composed predominantly of sheets of globoid and spindle-shaped crystal-storing histiocytes was detected incidentally in the right lung of a 72-year-old woman. Scattered lymphoplasmacytic aggregates within the tumor had monoclonality with anti-kappa immunoglobulin (Ig) M antibodies. The crystals were outlined positively by the same antibodies. They stained an intense blue with phosphotungstic acid-hematoxylin (PTAH) and were found during electron microscopy to be membrane bound and also within type I pneumocytes and the extracellular space. Excessive production of kappa IgM by neoplastic low-grade lymphoplasmacytoid cells of B-cell origin in an altered intra- or extracellular milieu may lead to crystallization and phagocytosis by reactive histiocytes. Review of the literature revealed seven more cases: four in the head and neck, and one each in the skin, the lymph node, and the lung. IgM was the most frequently crystallizing immunoglobulin (four of seven) and all had kappa light chains. The lesion needs to be differentiated from neoplastic and nonneoplastic histiocytic and lymphoplasmacytic disorders. The difference with bronchial mucosa-associated lymphoid tissue lymphoma and marginal zone lymphoma is, perhaps, semantic.

Subcutaneous panniculitis-like T-cell lymphoma: further evidence for a distinct neoplasm originating from large granular lymphocytes of T/NK phenotype

We report the case of a 20 year-old caucasian woman who presented a primary subcutaneous panniculitis-like T-cell lymphoma (SPTCL) as an invasive tumor of the chest wall. Herein, the neoplastic cells were found to express a CD3+CD8+ phenotype but also displayed variably the natural killer (NK)-associated antigens CD56 and CD57 as well as granzyme B. On cytological examination, these cells showed a large granular lymphocyte (LGL)-like morphology with presence of azurophilic granules in their cytoplasm. Electron dense and membrane bound granules like those found in cytotoxic T lymphocytes (CTL) were also demonstrated by electron microscopy. Neither rearrangement of the T-cell receptor subunits nor Epstein-Barr virus (EBV) genome was observed at the molecular level. The LGL-like features of the neoplastic cells found in this case and the presence of NK-associated antigens provide additional support to the cytotoxic derivation of most SPTCL.

Intracellular crystalline deposits in lymphoplasmacellular disorders

Crystalline immunoglobulin intracellular inclusions may be found in a range of B-cell neoplasias, including MALT (mucosa-associated lymphoid tissue) lymphoma. The crystals are regarded as an outcome of impaired cell secretory activity leading to their accumulation. At times the deposits may be so profound as to obscure the diagnosis and may even lead to misdiagnosis. Examples of the crystals are presented along with a brief literature review.