Differential diagnosis of this condition includes the Birt-Hogg-Dubé syndrome and tuberous sclerosis. As the skin lesions are typically painful, it is also often necessary to exclude other painful tumors of the skin (including blue rubber bleb nevus, leiomyoma, eccrine spiradenoma, neuroma, dermatofibroma, angiolipoma, neurilemmoma, endometrioma, glomus tumor and granular cell tumor; the mnemonic "BLEND-AN-EGG" may be helpful). Other skin lesions that may need to be considered include cylindroma, lipoma, poroma and trichoepithelioma; these tend to be painless and have other useful distinguishing features.

The skin lesions may be difficult to diagnose clinically but a punch biopsy will usually reveal a Grenz zone separating the tumour from the overlying skin. Histological examination shows dense dermal nodules composed of elongated cells with abundant eosinophilic cytoplasm arranged in fascicles (spindle cells). The nuclei are uniform, blunt-ended and cigar-shaped with only occasional mitoses. Special stains that may be of use in the diagnosis include Masson's trichrome, Van Gieson's stain and phosphotungstic acid–haematoxylin.

The renal cell carcinomas have prominent eosinophilic nucleoli surrounded by a clear halo.

Benign metastasizing leiomyoma is a rare condition characterized by the growth of uterine leiomyoma in the other regions especially the lungs.

Investigations by the physician include imaging (ultrasound, CAT scan, MRI) and, if possible, obtaining a tissue diagnosis by biopsy, hysteroscopy, or D&C.

Ultimately the diagnosis is established by the histologic examination of the specimen. Typically malignant lesions have >10 mitosis per high power field. In contrast a uterine leiomyoma as a benign lesion would have < 5 mitosis per high power field.

IFPs consist of spindle cells that are concentrically arranged around blood vessels and have inflammation, especially eosinophils.

They may have leiomyoma/schwannoma-like areas with nuclear palisading.

They typically stain with CD34 and vimentin, and, generally, do not stain with CD117 and S100.

The endoscopic differential diagnosis includes other benign, pre-malignant and malignant gastrointestinal polyps.

Unusual or postmenopausal bleeding may be a sign of a malignancy including uterine sarcoma and needs to be investigated. Other signs include pelvic pain, pressure, and unusual discharge. A nonpregnant uterus that enlarges quickly is suspicious. However, none of the signs are specific. Specific screening test have not been developed; a Pap smear is a screening test for cervical cancer and not designed to detect uterine sarcoma.

Intravenous leiomyomatosis is a rare condition seen exclusively in women in which leiomyomata, benign smooth muscle tumors, are found in veins. The masses are benign-appearing but can spread throughout the venous system leaving the uterus and even cause death when growing into the heart from the IVC. While the possibility that these arose de novo from the smooth muscle in the blood vessel wall was considered, chromosomal analysis suggests a uterine origin. Intravenous leiomyomata are usually but not always associated with uterine fibroids, and tend to recur.

This condition is related to benign metastasizing leiomyoma, in which the masses appear in more distant locations such as the lung and lymph nodes.

Angioleiomyoma (vascular leiomyoma, angiomyoma) of the skin is thought to arise from vascular smooth muscle, and is generally acquired.

Leiomyoma is the most common benign mesenchymal tumor of esophagus and second most common benign tumor of the small bowel (with gastrointestinal stromal tumor as most common). Although leiomyoma is the most common benign esophageal tumor, malignant carcinoma is still 50 times more likely. Approximately 50% of cases are found in the jejunum, followed by the ileum in 31% of cases. Almost one half of all lesions are less than 5 centimeters.

Mesothelial hyperplasia is a hyperplasia of mesothelial cells in serous membranes (pleura, pericardium, peritoneum).

Mesothelial hyperplasia is usually an incidental finding during peritoneal examination during laparotomy or laparoscopy. Grossly, mesothelial hyperplasia is characterized by the presence of small white nodules or flat plaques on the serous surface.

Mesenchymal neoplasms of the gallbladder are rare and in particular leiomyomas of the gallbladder have been rarely reported, all of them in patients with immune system disorders. Although, recently, a case was reported in absence of associated immunodeficiency at Monash Hospital in Melbourne Australia in a healthy 39-year-old woman with no symptoms.

To remove the tumor from the body, a myomectomy or hysterectomy is often required.

Solitary cutaneous leiomyoma typically presents as a deeply circumscribed, freely movable, rounded nodule ranging from 2 to 15mm in diameter, with overlying skin that may have a reddish or violaceous tint.

Inflammatory fibroid polyp, abbreviated IFP, is a benign abnormal growth of tissue projecting into the lumen of the gastrointestinal tract.

Surgery, with as wide a margin of removal as possible, has generally been the most effective and preferred way to attack LMS. If surgical margins are narrow or not clear of tumor, however, or in some situations where tumor cells were left behind, chemotherapy or radiation has been shown to give a clear survival benefit. While LMS tends to be resistant to radiation and chemotherapy, each case is different and results can vary widely.

LMS of uterine origin do frequently, but not always respond to hormonal treatments.

Treatment of Meigs' syndrome consists of thoracentesis and paracentesis to drain off the excess fluid (exudate), and unilateral salpingo-oophorectomy or wedge resection to correct the underlying cause.

They are of two types.

- The leiomyoma occurs in the skin or gut but the common form is the uterine fibroid.

- Rhabdomyomas are rare tumors of muscles, they occur in childhood and often become malignant.

The diagnosis of a mediastinal germ cell tumor should be considered in all young males with a mediastinal mass. In addition to physical examination and routine laboratory studies, initial evaluation should include CT of the chest and abdomen, and determination of serum levels of HCG and alpha-fetoprotein.

1.SMA, smooth muscle actin. 2.MSA, muscle-specific actin. 3.EMA, epithelial membrane antigen.

Smooth muscle tumor of uncertain malignant potential, abbreviated STUMP, is an uncommon tumor of the uterine smooth muscle that may behave like a benign tumor or a cancerous tumor.

This tumor should not be confused with the prostatic stromal tumor of uncertain malignant potential which may be abbreviated the same way ("STUMP").

The Bell criteria were developed to help categorize them and differentiate them from their main differential diagnoses, leiomyosarcoma and uterine leiomyoma.

Evaluation of the mitotic figures in a STUMP requires evaluation of 3 specific criteria

1. Hairy extensions of chromatin must be present, extending from a central clot-like dense mass of chromosomes. Hairy extensions from an empty center favor a non-mitosis. Count 4 sets of 10 fields in the area of highest mitotic activity and use the highest count

2. No nuclear membrane

3. Rule out lymphocytes, mast cells, stripped nuclei, degenerated cells, and precipitated hematoxylin.

The presence of a uterine fibroid versus an adnexal tumor is made. Fibroids can be mistaken for ovarian neoplasms. An uncommon tumor which may be mistaken for a fibroid is Sarcoma botryoides. It is more common in children and adolescents. Like a fibroid, it can also protrude from the vagina and is distinguished from fibroids. While palpation used in a pelvic examination can typically identify the presence of larger fibroids, gynecologic ultrasonography (ultrasound) has evolved as the standard tool to evaluate the uterus for fibroids. Sonography will depict the fibroids as focal masses with a heterogeneous texture, which usually cause shadowing of the ultrasound beam. The location can be determined and dimensions of the lesion measured. Also, magnetic resonance imaging (MRI) can be used to define the depiction of the size and location of the fibroids within the uterus.

Imaging modalities cannot clearly distinguish between the benign uterine leiomyoma and the malignant uterine leiomyosarcoma, however, the latter is quite rare. Fast growth or unexpected growth, such as enlargement of a lesion after menopause, raise the level of suspicion that the lesion might be a sarcoma. Also, with advanced malignant lesions, there may be evidence of local invasion. A biopsy is rarely performed and if performed, is rarely diagnostic. Should there be an uncertain diagnosis after ultrasounds and MRI imaging, surgery is generally indicated.

Other imaging techniques that may be helpful specifically in the evaluation of lesions that affect the uterine cavity are hysterosalpingography or sonohysterography.

The differential diagnosis of serous carcinoma not otherwise specified includes:

- Ovarian serous carcinoma, a type of ovarian cancer.

- Uterine serous carcinoma, also known as "uterine papillary serous carcinoma", a type of uterine cancer.

- Fallopian tube serous carcinoma, a type of uterine tube cancer.

- Cervical serous carcinoma, a rare type of cervical cancer.

- Primary peritoneal serous carcinoma, a very rare cancer that arise from the peritoneum.

There has been the suggestion that the above diagnoses really represent one entity.

Meigs syndrome may mimic other conditions, since it is tumor arising from ovaries, pathology of any organs present in the abdomen may show a similar set of symptoms. Various gynecological disorders of the uterus such as endometrial tumor, sarcoma, leiomyoma (pseudo-Meigs syndrome); fallopian tube disorders such as hydrosalpinx, granulomatous salpingitis, fallopian tube malignancy; ovarian disorders such as serous, mucinous, endometrioid, or clear cell carcinoma, Brenner tumor, granulosa cell tumor, stromal tumor, dysgerminoma, fibroma, or metastatic tumor to the ovary.

Meigs syndrome is characterized by the presence of a benign solid ovarian tumor associated with ascites and right hydrothorax that disappear after tumor removal. Non-gynecological manifestations include:

ascites, portal vein obstruction, inferior vena cava obstruction, hypoproteinaemia, thoracic duct obstruction, tuberculosis, amyloidosis, pancreatitis, ovarian hyperstimulation, pleural effusion transudative, congestive heart failure, metastatic tumors to the peritoneal surfaces, collagen-vascular disease, and cirrhosis of the liver.

These entities must be clinically excluded.

Clinical condition characterized by ovarian mass, ascites, and right-sided pleural effusion.Ovarian malignancy and the

other causes (see “Differential Diagnosis”) of pelvic mass, ascites, and pleural effusion to be considered, History of early satiety,

weight loss with increased abdominal girth, bloating, intermittent abdominal pain, dyspnea, nonproductive cough may help in differentiating potential local factor causing such symptoms.

Myxomas are usually removed surgically. The surgeon removes the myxoma, along with at least 5 surrounding millimeters of atrial septum. The septum is then repaired, using material from the pericardium.