Imaging of salivary gland cancers derived from a sublingual gland herniated into the submandibular space: a report of three cases

Sublingual gland herniation into the submandibular space through a mylohyoid muscle defect is a common anatomical variation; however, salivary gland cancers that arise from a herniated sublingual gland have not been described yet. Here, we report three patients with salivary gland cancers originating from a herniated sublingual gland. All tumors were detected as palpable submandibular masses, located anterior to the submandibular gland, medial to the mandible, and lateral to the mylohyoid muscle, with contact with the sublingual gland through a mylohyoid muscle defect. Intraoperative findings confirmed that the masses were derived from herniated sublingual glands. Pathological examination showed one case of mucoepidermoid carcinoma and two cases of adenoid cystic carcinoma. Imaging findings of the tumor location, in addition to the continuity with the sublingual gland through the mylohyoid muscle defect, are crucial for accurately diagnosing the tumor origin, which is essential for determining the appropriate clinical management.

Extraoral type of intraductal papilloma in sublingual gland

INTRODUCTION

It is rare for intraductal papilloma (IDP), a benign papillary tumor, to occur in the sublingual gland (SLG).

CASE SUMMARY

A 55-year-old man incidentally found a painless mass in his left submandibular region (SMR). He had a history of two surgeries for bilateral SLG cyst. Contrast enhanced ultrasound (CEUS) and magnetic resonance imaging (MRI) were performed. The patient received trans-cervical excision of left residual SLG in combination with excision of left submandibular gland (SMG). The postoperative course was uneventful and no signs of recurrence during 5 months of follow-up.

DISCUSSION

For a SMR mass, extraoral type of IDP in SLG should be considered in the differential diagnosis.

One case of sublingual gland mucosa-associated lymphoid tissue lymphoma

Mucosa-associated lymphoid tissue (MALT) lymphoma is a type of marginal zone B-cell lymphoma that occurs outside the lymph nodes in mucosal tissue. It accounts for 6-8 % of non-Hodgkin's lymphomas. MALT lymphoma of the salivary gland is a rare disease, with primary tumors in the salivary gland accounting for 2-5 % of salivary gland tumors. The most common site is the parotid gland (80 %), followed by the submandibular gland (14 %), minor salivary glands, and sublingual gland (5 %). Patients with salivary gland MALT lymphoma often have autoimmune diseases such as Sjogren's syndrome and rheumatoid arthritis. Primary malignant tumors of the sublingual gland account for less than 1 % of cases, and preoperative diagnosis is difficult, often requiring biopsy for confirmation. To our knowledge, there are no reports of MALT lymphoma arising from the sublingual gland. We report a case of MALT lymphoma originating from the sublingual gland in a patient with a history of hypertension, diabetes, cerebral infarction, and non-traumatic numbness of the right lower limb.

Non-neoplastic salivary gland diseases in children: a 10-year review at a tertiary center

OBJECTIVES

Non-neoplastic salivary gland diseases are rare in children. This paper aims to present the spectrum of encountered non-neoplastic salivary gland diseases at a tertiary center by describing the demographics, clinical characteristics, and outcomes in this patient population.

METHODS

A review of electronic medical records was performed from 2010 until 2020. Relevant data were retrieved and charted according to the type of salivary gland disease. A comparison between diseases was made for demographics, presenting symptoms, treatment, and outcomes.

RESULTS

Fifty patients with 11 different non-neoplastic salivary gland diseases were identified. Sialolithiasis was the most prevalent condition (12/50), with 83% localized in the submandibular gland. In contrast to gender, age, and symptoms, the location of pathology was significantly associated with the diagnosis (p < 0.001). In patients with sialolithiasis, a hybrid procedure (combined endoscopy and lithotomy) resulted in 100% resolution of symptoms. For (plunging) ranula, marsupialisation had a relative risk of recurrence of 9.6 compared to (partial) extirpation of the sublingual gland.

CONCLUSIONS

Children with salivary gland diseases present with overlapping symptoms, making clinical diagnosis challenging. The present study may aid physicians and specialists in diagnosing the most prevalent conditions in children. Although no gold standards exist for their treatment, hybrid procedures (sialolithiasis) and subglingual gland extirpation (ranula) showed superior results over alternatives.

Prognostic factors for sublingual gland carcinoma: a population-based Surveillance, Epidemiology and End Results database study

OBJECTIVE

To identify the clinical features and prognostic factors for sublingual gland carcinoma.

METHODS

This was a case-control study. Patients with surgically treated sublingual gland carcinoma were retrospectively included in the Surveillance, Epidemiology and End Results database and divided into adenoid cystic carcinoma (ACC) and non-ACC groups. Primary outcome variables were disease-specific survival (DSS) and overall survival (OS). Prognostic factors for each group were analyzed using Cox models.

RESULTS

We included 251 patients (115 men and 136 women). Compared with the non-ACC group, the ACC group had a larger average tumor size and received more adjuvant radiotherapy. In patients with ACC, the pathologic grade had an independent impact on DSS and OS, and patients who were undergoing adjuvant chemotherapy had worse DSS than those who were not receiving chemotherapy. In the non-ACC group, pathologic grade IV, lymph node metastasis, and adjuvant chemotherapy were associated with poor DSS and OS, and tumor extension predicted worsening DSS.

CONCLUSIONS

In sublingual gland carcinoma, the pathologic grade and adjuvant chemotherapy were the most important prognostic factors, whereas lymph node metastasis had a negative impact in non-ACC patients but not in ACC patients.

Palisading Adenocarcinoma: A Morphologically Unique Salivary Gland Tumor With a Neuroendocrine-like Appearance and a Predilection for the Sublingual Glands of Women

Adenocarcinoma, not otherwise specified (NOS) is a heterogenous group of salivary gland tumors that likely contains distinct tumors that have not yet been characterized. Indeed, in recent years, cases previously diagnosed as adenocarcinoma, NOS have been recategorized into novel tumor designations such as secretory carcinoma, microsecretory adenocarcinoma, and sclerosing microcystic adenocarcinoma. We sought to describe a distinctive, hitherto-undescribed salivary gland tumor encountered in the authors' practices. Cases were pulled from the surgical pathology archives of the authors' institutions. Histologic, immunohistochemical, and clinical findings were tabulated, and targeted next-generation sequencing was performed on all cases. Nine cases were identified, arising in 8 women and 1 man ranging from 45 to 74 years (mean, 56.7 y). Seven tumors (78%) arose in the sublingual gland, while 2 (22%) arose in the submandibular gland. The cases shared a distinctive morphologic appearance. They were biphasic, with ducts scattered among a predominant polygonal cell with round nuclei, prominent nucleoli, and pale eosinophilic cytoplasm. These cells were arranged as trabeculae and palisaded as pseudorosettes around hyalinized stroma and vessels, resembling a neuroendocrine tumor. Four of the cases were well-circumscribed, while the remaining 5 showed infiltrative growth including perineural invasion in 2 (22%) and lymphovascular invasion in 1 (11%). Mitotic rates were low (mean, 2.2/10 HPFs); necrosis was absent. By immunohistochemistry, the predominant cell type was strongly positive for CD56 (9 of 9) and variably positive for pan-cytokeratin (AE1/AE3) (7 of 9) with patchy S100 (4 of 9), but negative for synaptophysin (0 of 9) and chromogranin (0 of 9), while the ducts were strongly positive for pan-cytokeratin (AE1/AE3) (9 of 9) and CK5/6 (7 of 7). Next-generation sequencing did not reveal any fusions or obvious driver mutations. All cases were resected surgically, with external beam radiation also done in 1 case. Follow-up was available in 8 cases; there were no metastases or recurrences after 4 to 160 months (mean, 53.1 mo). A dual population of scattered ducts with a predominance of CD56-positive neuroendocrine-like cells characterizes a unique salivary gland tumor which is often encountered in the sublingual glands of women, for which we propose the term "palisading adenocarcinoma." Although the tumor was biphasic and had a neuroendocrine-like appearance, it lacked convincing immunohistochemical evidence of myoepithelial or neuroendocrine differentiation. Although a subset showed unequivocally invasive growth, this tumor appears to behave in an indolent manner. Moving forward, recognition of palisading adenocarcinoma and its separation from other salivary adenocarcinomas, NOS will facilitate a better understanding of the characteristics of this previously unrecognized tumor.

Lymphomas Affecting the Sublingual Glands: A Clinicopathological Study

BACKGROUND

Lymphomas affecting the sublingual glands are extremely rare and very few case reports are currently available. Therefore, the aim of the current study is to describe the clinicopathological features of a series of lymphomas involving the sublingual glands.

METHODS

Cases diagnosed in four pathology services were assessed and the formalin-fixed paraffin-embedded tissue blocks were retrieved for diagnosis confirmation. Clinical data were obtained from patients' medical files.

RESULTS

We obtained seven cases of lymphomas in the sublingual glands, representing two follicular lymphomas, two diffuse large B cell lymphomas not otherwise specified (DLBCL NOS), two extranodal marginal zone B cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphomas) and one mantle cell lymphoma (MCL). In all cases the tumor cells infiltrated the glandular parenchyma, although in two of them the neoplastic cells were located more superficially and permeated the glandular acini and ducts. Clinically, the tumors presented as asymptomatic nodules and two patients (affected by DLBCL NOS and MCL) died, while the other five patients remained alive at last follow-up.

CONCLUSION

Lymphomas affecting the sublingual glands are usually of the mature B cell lineage, often represent low-grade subtypes and may clinically resemble other more common lesions in the floor of the mouth like salivary gland tumors.

Adenoid cystic carcinoma of the sublingual gland developing lung metastasis 20 years after primary treatment: A case report and literature review

RATIONALE

Adenoid cystic carcinoma (ACC) is a rare malignant tumor that primarily occurs in the salivary glands. Distant metastases can develop despite favorable local control. Moreover, distant metastasis of ACC can occur after a long time interval without local recurrence. We report the first case of ACC of the sublingual gland that developed lung metastasis 20 years after primary treatment.

PATIENT CONCERNS

A 52-year-old man was referred to our department with a 1-year history of painful swelling on the right oral floor.

DIAGNOSIS

An incisional biopsy was performed, and histopathological examination revealed malignancy.

INTERVENTIONS

Surgical excision of the right oral floor and right supra-omohyoid neck dissection with postoperative chemoradiation therapy were performed, and ACC of the sublingual gland was diagnosed. Left pulmonary metastasis was detected 20 years after the primary treatment. Metastasectomy was performed; however, subsequently, skin and bone metastases developed.

OUTCOMES

After receiving palliative care, the patient died of multiple organ failure.

LESSONS

As late distant metastasis of salivary ACC can develop, patients who undergo primary treatment need a long-term, strict follow-up plan even if locoregional control is favorable.

Comprehensive histochemical and stereological study of the parotid and sublingual salivary glands in Caucasian squirrel (Sciurus anomalus)

The present investigation tries to reflect histochemical and stereological properties of the parotid gland (PG) and sublingual gland (SLG) in the Caucasian squirrel. Totally, five male Caucasian squirrels were used. The glands were examind histochemical using PAS, Alcian blue (AB, pH = 2.5) and Aldehyde fucshin (AF) stainings. Total volume of the glands, acini, ducts as well as total length of ducts were estimated using streological procedures. The PG had a unique morphology and were connected to each other with an intermediated isthmus. The SLG was oval-shaped. Serous acini of PG exhibited strong, negative and weak reaction with AF, AB and PAS, respectively. While, mucous acini of SLG showed positive staining for AB and PAS, and negative staining for AF. The ductal system was consisted of intercalated (Id), striated (SD) and excretory ducts (Ed). The Sd in PG was lined with simple cuboidal to the columnar epithelium, while it was lined with simple cuboidal epithelium in SLG. The Ed was lined with stratified cuboidal epithelium in both glands. The striated duct was longest duct in both glands, the excretory and intercalated ducts were the shortest ones in PG and SLG, respectively. The maximum total volume in both gland were blonged to the acini and straited ducts. It concluded that PG and SLG in the Caucasian squirrel have some distinct structural properties in comparison to other rodents and mammalis species.

Sublingual Nodules: Diagnostic Markers of Metastatic Breast Cancer

OBJECTIVE

To evaluate the diagnostic significance of sublingual nodules for metastasis of patients with breast cancer and further to explore the mechanisms of sublingual nodules.

METHODS

The image data of 117 in-patients with breast cancer in stage I-IV in Tianjin Medical University Cancer Institute and Hospital from December 2009 to September 2011 were assessed retrospectively. All photos of patients' tongue were recorded by the digital camera of uniform type within 1 month after serological examination and regular re-examined by computed tomography (CT), magnetic resonance imaging and positron emission tomography CT. The presence of sublingual nodules was the positive standard. Chi square test and two-independent-sample test were used to determine the diagnostic value between the status of sublingual nodules and Clinico-pathological characteristics. The optimal cut-off of uric acid (UA) level to diagnose sublingual nodules was determined by receiver operating curve (ROC) analysis.

RESULTS

Breast cancer patients with sublingual nodules had a higher risk of recurrence and/or metastasis than patients without it (P<0.001). Sublingual nodules was significantly correlated with increased serum UA level (P=0.001). The optimal cut-off value of UA level to diagnose sublingual nodules was 290 μmol/L. Furthermore, the elevated serum UA level (≥290 μmol/L) was significantly related to breast cancer recurrence and/or metastasis (P<0.001).

CONCLUSIONS

Sublingual nodules were potential diagnostic markers for metastatic breast cancer. The formation of sublingual nodules was associated with elevated level of serum UA.

[Cerebral infarction in a patient with primary Sjogren's syndrome: a case report and literature review]

Sjogren's syndrome (SS) is a chronic autoimmune disorder characterized by lymphocytes infiltration in the exocrine glands. Central nervous system complications of primary SS are not rare, but ischemic stroke has been rarely reported. Here we report a 43-year-old female with a two-year history of primary SS, presenting with sudden cerebral infarction. Her primary SS was diagnosed on the basis of clinical features, high levels of serum anti-SSA and anti-SSB antibodies, salivary gland secretion evaluation and positive sublingual gland biopsy results. Magnetic resonance imaging revealed infarct lesions in the parietal and occipital lobes, as well as in the left basal ganglia. Magnetic resonance angiography showed a remarkable stenosis in the left middle cerebral artery. Other differential diagnoses were ruled out. Corticosteroid and immunosuppressor, together with anti-platelet and statin were effective, and the patient recovered quickly without sequelae. Based on these findings, vasculitis due to primary SS should be considered among the causes of stroke. The literature was reviewed and the relationship between primary SS and cerebral infarction explored. The pathogenesis of ischemic stroke in primary SS is still unknown and warrants further studies.

Does Leishmaniasis disease alter the parenchyma and protein expression in salivary glands?

Leishmaniasis is considered a serious public health problem in several regions in Brazil and worldwide. This research aimed to perform a histopathological and proteomic study of parotid, submandibular and sublingual glands of BALB/c mice infected by Leishmania (L) infantum chagasi using histological, immunohistochemical and epifluorescence techniques. Twelve isogenic BALB/c male mice, around six- to eight-weeks old, were separated into two groups: the animals of the control group were injected with 0.15 ml of NaCl, while those in the experimental group were inoculated with 5 × 10(6) amastigote forms of Leishmania (L) infantum chagasi by the ip route. After 50 days, animals were euthanized and major salivary glands were collected to perform histological, immunohistochemical and epifluorescence techniques using anti-Caspase-2, anti-Ki-67 and anti-β-catenin antibodies, respectively. The histological and morphometric evaluation showed clusters of mononuclear inflammatory cells and a higher area and perimeter of the parotid gland. However, none of the salivary glands had morphophysiological impairment. There was no immunoreactivity to the anti-caspase-2 antibody and Ki67 expression in acinar and ductal cells in both groups. According to the immunofluorescence staining, the β-catenin antibodies did not show nuclear expression, suggesting no uncontrolled proliferation. The data obtained in this study showed population and morphological stability of major salivary glands after 50 days post-infection by Leishmania (L) infantum chagasi.

Isolated Langerhans cell histiocytosis of the sublingual gland in an adult

Langerhans cell histiocytosis (LCH) is a rare disorder characterized by the proliferation of pathologic Langerhans cells. Its clinical presentation is highly variable, that range from single-system, limited disease to severe, multi-organ disease with high mortality. LCH usually affects children and young adults. The most frequent sites for LCH are the bone, skin, lung, pituitary gland, and lymph nodes. Salivary gland involvement by LCH is extremely rare, and only a few cases of LHC involving the parotid glands have been reported in the English literature. To our knowledge, the involvement of the sublingual gland as a part of single or multisystem LCH has not been previously described. Herein we reported the first case of primary LCH of the sublingual gland. A 40-year-old woman presented with a 2-month history of a painless mass on the right sublingual area. Excision of the lesion including the right sublingual gland was performed. Histopathological diagnosis of LCH was rendered. The patient remains free of symptoms 17 months after surgery.

Morphological differences in innervation between mucous glands and serous glands: a quantitative histological study using the sublingual glands of elderly humans

CONCLUSION

In the sublingual gland, the serous lobule usually carried a higher density of NSE-positive nerve elements than the mucous lobule, whereas the mucous acinus in the mucous lobule was larger than the serous acinus in the serous lobule.

OBJECTIVES

To demonstrate quantitative differences in nerve elements between the mucous and serous lobules of sublingual glands.

METHODS

This study investigated using specimens from 14 donated cadavers (mean age = 78 years). Since immunohistochemistry for neuron-specific enolase (NSE) stains all nerves in addition to other mesenchymal cells possibly of nerve origin, the present quantitative evaluation was based on NSE-positive areas per visual field under a ×20 objective lens (0.6 × 0.45 mm when printed).

RESULTS

In mucous lobules, the areas occupied by NSE-positive nerve elements ranged from 5798-16,541 μm(2) (mean ± SD = 9280 ± 2584 μm(2)). In contrast, the corresponding areas in serous lobules ranged from 7853-23,540 μm(2) (mean ± SD = 13,520 ± 4351 μm(2)). The difference in NSE-positive areas was statistically significant (p = 0.0022). However, the mucous acinus in the mucous lobule was 2-times larger than the serous acinus in the serous lobule (2474 ± 1477 μm(2) vs 1119 ± 632 μm(2)).

Plunging ranula: an unusual multilocular presentation

A 32-year-old male patient who was HIV positive presented at the Wits Oral Health Centre complaining of a large swelling of the left submandibular region of three years' duration. The swelling was nontender, soft and doughy on palpation and appeared to be crossing the midline. Bilateral submandibular and submental lymphadenopathy was present. Intraorally the lesion caused considerable elevation of the floor of the mouth and impaired the flow of saliva. Fluid from the lesion was aspirated and the patient sent for MRI examination. These images revealed a multilocular cystic lesion causing disruption of the mylohyold muscle. The aspirate consisted of a thick, bloody fluid which tested positive for salivary amylase. A provisional diagnosis of plunging ranula was made. The multilocular nature of the lesion seen on MRI prompted a more extensive surgical approach in order to prevent recurrence. Consequently the sublingual gland was removed via an intraoral approach while the multilocular cyst was dissected by means of a submandibular approach in order to effect complete removal. Microscopic examination of the submitted specimen confirmed the clinical diagnosis of a plunging ranula.

Dynamic sonography and CT findings of unilateral submandibular gland agenesis associated with herniated hypertrophic sublingual gland

Congenital agenesis of the submandibular gland is uncommon. We report dynamic sonography and CT findings of the unilateral submandibular gland agenesis associated with herniated hypertrophic sublingual gland tissue through the mylohyoid gap. The dynamic sonography examination applied at rest and during the modified Valsalva maneuver demonstrated hypertrophied sublingual gland prolapsing to the anterior part through the mylohyoid gap. This may be the first reported case describing dynamic sonography findings of this entity. CT confirmed the agenesis of the left submandibular gland and compensatory hypertrophy of the ipsilateral sublingual gland.

[Sublingual gland amyloidosis causing obstructive sleep apnea hypopnea syndrome: a case report and review of the literatures]

OBJECTIVE

To improve the understanding of sublingual gland amyloidosis causing obstructive sleep apnea hypopnea syndrome(OSAHS).

METHODS

A case of sublingual gland amyloidosis causing OSAHS diagnosed in april 2012 was reported and the related literatures were reviewed. The literature review was carried out respectively with "amyloidosis, sublingual gland, obstructive sleep apnea hypopnea syndrome", as the search terms in Wanfang Data and PubMed by November 2012.

RESULTS

A case of 74 year-old male patient was admitted to the hospital because of snoring for 5 years, sleep apnea for 1 year and arousal for 1 month. After admission, polysomnography showed severe OSAHS, physical examination showed redundant the sublingual gland. Enhanced CT scanning showed soft tissue masses at the sublingual gland. Abdominal B ultrasonic and CT also showed a spaces-occupying lesion in the left retroperitoneal. B-guided core needle biopsy was performed in the left retroperitoneal. Pathology report showed amyloidosis. Subsequently, sublingual gland mass resection was performed. Pathology report after operation showed amyloid deposits staining with Congo red, which gives it a characteristic green birefringence in polarised light. Accordingly, it was diagnosed as sublingual gland amyloidosis. The symptoms of snore and sleep apnea were disappeared after operation.So far, there was no local recurrence with 10 months follow-up. A total of 3 literatures were received in Wanfang Data, including 2 of macroglossia amyloidosis causeing OSAHS case report and one of retrospective study. There were no reports about sublingual gland amyloidosis in Wanfang Data. A total of 5 literatures were received in Pubmed, including 2 of sublingual gland amyloidosis case report, 2 of macroglossia amyloidosis causeing OSAHS case report and one of retrospective study. However, there were no reports about sublingual gland amyloidosis causing OSAHS.

CONCLUSIONS

Amyloidosis rarely occurred in the sublingual gland and is easy to be misdiagnosed and missed diagnosed, which can causing severe OSAHS. To make a definite diagnosis, histopathology and staining with Congo red are needed and a characteristic green birefringence in polarised light is a reliable marker for diagnosis. After sublingual gland mass resection, the patient had good prognosis.

The plunging ranula: diagnostic difficulties and a less invasive approach to treatment

Plunging ranulas arise when a simple ranula extends beyond the floor of the mouth into the neck. Diagnosis is difficult even with modern imaging techniques as they mimic other neck lesions, and traditional treatment involves enucleation of the cyst from the neck. Despite this invasive surgery they tend to recur. We describe a less invasive approach to treatment and review the diagnostic pitfalls. From 2002 to 2011, eight patients presented with a plunging ranula. They were split into two groups: those for whom an incorrect diagnosis was made and those where a less invasive treatment approach was employed. Three patients were misdiagnosed with cervical lymphangioma and had inappropriately invasive surgery. Five patients with established plunging ranulas were treated using an intraoral approach alone, eliminating the need for a cervical incision. Misdiagnosis of a plunging ranula leads to extensive and unnecessary surgery. We propose an algorithm to simplify investigation that employs a low threshold for fine-needle aspiration cytology. The cases presented indicate that these lesions can be managed by a less invasive procedure than currently practised.

Anterior lingual mandibular bone depression in an 11-year-old child

This report describes physical and imaging findings in a case of anterior lingual mandibular bone depression in a child. This entity is very rarely diagnosed and even more extremely rarely seen in children. We present some characteristic findings depicted on images provided by different sources and briefly address current hypotheses on its pathogenesis.

Plunging ranula

Plunging ranulas are rare cystic masses in the neck that are mucous retention pseudocysts from an obstructed sublingual gland. They "plunge" by extending inferiorly beyond the free edge of the mylohyoid muscle, or through a dehiscence of the muscle itself, to enter the submandibular space. Imaging demonstrates a simple cystic lesion in the characteristic location and can be used to delineate relevant surgical anatomy. Surgical excision of the collection and the involved sublingual gland is performed for definitive treatment. We present a case of plunging ranula in a 44 year old female who presented with a painless, slowly enlarged neck mass. Plunging ranulas should be considered in the differential diagnosis of cystic neck masses, specifically when seen extending over, or through, the mylohyoid muscle.

Oto-Rhino-Laryngology (ORL) tumor presentation in a case of systemic AA amyloidosis

A 64-year-old male with no underlying disease presented with the development of multiple skin nodules, loss of sensation in the extremities, hoarseness, macroglossia, and pain in the oral cavity. Direct laryngoscopy showed nodules involving the oral cavity, oropharynx, supraglottic region, and vocal cords. Biopsy from skin nodules showed amyloid deposits staining with Congo red. Immunohistochemical staining was used for AA protein and was positive. Biopsy from the oral floor was also positive for amyloid. Oto-Rhino-Laryngology (ORL) involvement has been reported in approximately 40 percent of AL amyloidosis patients, but does not appear to be frequent in AA amyloidosis. Cutaneous manifestations in AA amyloidosis are rare, although cases with lesions presenting as purpura are reported occasionally; we are not aware of other cases of ORL nodular involvement in systemic AA.